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Posted by: imran Sep 24 2005, 04:23 PM

This NASA Discovery mission is to be launched in June 2008 and will search for Earth-size and smaller planets. Launch was originally scheduled in 2007 but delayed by 8 months due to "funding constraints".

Here's the official web site:
http://www.kepler.arc.nasa.gov/

Posted by: ljk4-1 Dec 12 2005, 04:02 PM

Paper: astro-ph/0512251

Date: Fri, 9 Dec 2005 16:01:29 GMT (988kb)

Title: The Effect of the Transit of Venus on ACRIM's Total Solar Irradiance
Measurements: Implications for Transit Studies of Extrasolar Planets

Authors: G. Schneider, J. M. Pasachoff and R. C. Willson

Comments: Accepted to ApJ 8 Dec 2005; 14 pages of text, 8 figures, 1 table
\\
We used the 8 June 2004 transit of Venus (ToV) as a surrogate to test
observing methods, strategies and techniques that are being contemplated for
future space missions to detect and characterize extrasolar terrestrial planets
(ETPs) as they transit their host stars, notably NASA's Kepler mission planned
for 2008. As an analog to "Kepler-like" photometric transit observations, we
obtained (spatially unresolved) radiometric observations with the ACRIM 3
instrument on ACRIMSAT to follow the effect of the ToV on the total solar
irradiance (TSI). Contemporaneous high-resolution broadband imagery with NASA's
TRACE spacecraft provided, directly, measures of the stellar (solar)
astrophysical noise that can intrinsically limit such transit observations.
During the ~ 5.5 h transit, the planet's angular diameter was approximately
1/32 the solar diameter, thus covering ~ 0.1 of the stellar surface. With our
ACRIM 3 data, we measure temporal changes in TSI with a 1 sigma per sample
(unbinned) uncertainty of approximately 100 mW m^-2 (0.007%). A diminution in
TSI of ~ 1.4 W m^-2 (~ 0.1%, closely corresponding to the geometrically
occulted area of the photosphere) was measured at mid-transit compared with a
mean pre/post transit TSI of ~ 1365.9 W m^-2. These observations serve as a
surrogate to future photometric observations of ETPs such as Kepler will
deliver. Detailed analysis of the ToV, a rare event within our own solar
system, with time-resolved radiometry augmented with high-resolution imagery
provides a useful analogue for investigating the detectability and
characterization of ETPs from observations that are anticipated in the near
future.

\\ ( http://arXiv.org/abs/astro-ph/0512251 , 988kb)

Posted by: ljk4-1 Jan 10 2006, 03:51 PM

Astrophysics, abstract
astro-ph/0601186

From: Gyula Szabo [view email]

Date: Mon, 9 Jan 2006 16:10:04 GMT (132kb)

Possibility of a photometric detection of "exomoons"

Authors: Gy. M. Szabo, K. Szatmary, Zs. Diveki, A. Simon

Comments: 5 pages, 4 figures, accepted by Astronomy and Astrophysics

We examined which exo-systems contain moons that may be detected in transit. We numerically modeled transit light curves of Earth-like and giant planets that cointain moons with 0.005--0.4 Earth-mass. The orbital parameters were randomly selected, but the entire system fulfilled Hill-stability. We conclude that the timing effect is caused by two scenarios: the motion of the planet and the moon around the barycenter. Which one dominates depends on the parameters of the system.

Already planned missions (Kepler, COROT) may be able to detect the moon in transiting extrasolar Earth-Moon-like systems with a 20% probability. From our sample of 500 free-designed systems, 8 could be detected with the photometric accuracy of 0.1 mmag and a 1 minute sampling, and one contains a stony planet. With ten times better accuracy, 51 detections are expected. All such systems orbit far from the central star, with the orbital periods at least 200 and 10 days for the planet and the moon, while they contain K- and M-dwarf stars.

Finally we estimate that a few number of real detections can be expected by the end of the COROT and the Kepler missions.

http://arxiv.org/abs/astro-ph/0601186

Posted by: ljk4-1 Jan 19 2006, 07:16 PM

Science/Astronomy:

* Close-Up on the Kepler Mission

http://www.space.com/searchforlife/seti_kepler_060118.html

The next transit of an Earth-sized planet will likely be observed in 2007 by the NASA Discovery Program's Kepler Mission. But the event won't happen in our solar system.

* Asteroid Collision Fueled Ancient Dust Storm on Earth

http://www.space.com/scienceastronomy/060118_asteroid_dust.html

One of the biggest cosmic dust storms of the past 80 million years left a blanket of material on Earth after an asteroid in space broke apart, researchers said today.

Posted by: Redstone Mar 29 2006, 07:46 PM

According to the Kepler website, which doesn't look like it has been updated for a while, the Critical Design Review for Kepler was supposed to happen in February. Does anyone know if it happened, whether Kepler passed, and if it has enterred ATLO yet? We've heard second hand reports via Bruce that the budget has been busted, but that NASA will keep the money flowing. But has the project moved much lately?

Posted by: Toymaker Mar 30 2006, 01:05 PM

I am interested in it as well
Well I downloaded the NASA's budget document and it seems that Kepler is going to be launched...unless I interpret the language in wrong way:
http://www.nasa.gov/pdf/142458main_FY07_budget_full.pdf
But the ATLO you speak about is written in the document as only to be conducted.
I am really interested and hope somebody could share a light on this.

Posted by: BruceMoomaw Mar 30 2006, 06:36 PM

Latest news is that the launch is currently set for mid-2008. They seem determined not to cancel it, although there may be further delays. (Once again, we have dramatic evidence of the extent to which Discovery proposers are tempted to understate their mission's cost and then try to persuade NASA to go along with it anyway. I hope Dawn hasn't set a disastrous precedent in this, or the Solar System Groupies may have shot themselves badly in the foot by demanding that it not be cancelled.)

Posted by: GravityWaves Mar 31 2006, 02:57 AM

Looks like a great mission,
we've got loads of exoplanet missions Corot, Kepler, TPF and Darwin ( If the budget stays good then NASA have some great exoplanet mission plans - unless of course NASA continues to hacking bits off TPF until there's nothing left )

Posted by: PhilHorzempa Apr 3 2006, 08:59 PM

Today, I noticed that the Kepler web site schedule has been updated. Launch has been slipped
by 4 months due to fiscal matters, and is now scheduled for October 2008. In addition, the
Critical Design Review is scheduled for this month, April 2006.

In addition, Kepler will now feature a fixed High Gain antenna, instead of featuring a gimbal.
According to the website, this was done to reduce risk, cost and complexity. However, this
means that Kepler will miss 1 day's worth of observing per month.

Posted by: PhilHorzempa May 22 2006, 03:05 AM

This is targeted at those with some familiarity with sources of Astronomical
images. I am including links to the planned Field of View (FOV) for the Kepler
mission. The first page links to a brief description of the FOV's location, while
the second link is a more detailed pdf of the FOV itself.

http://kepler.nasa.gov/sci/basis/fov.html

http://kepler.nasa.gov/sci/basis/images/New_FOV_6m.pdf



What I am looking for would be telescope images of the FOV, showing the
star fields in some detail. I have searched the Kepler web site, but there are
no such telescopic photos there. I think that is a shame. Kepler's mission involves
searching for extra-solar planetary transits using a fancy photometer. The resulting
light curves will be great to analyze, but the public (including me) will want to
see just what Kepler was looking at.

I think that a mosaic of images of the target FOV Milky Way star field should
be magnificent. To me, such public outreach should be something that the Kepler
team would want to pursue.


Another Phil

Posted by: remcook May 22 2006, 09:58 AM

Are there known transiting exoplanets in that piece of sky for cross-checking purposes?

Posted by: angel1801 May 22 2006, 02:07 PM

I know two exo-planets have been discovered by the use of the transit method. However, the only planet that could be used to calibrate or test such technologies at the current time is Venus. Scientists used the June 8, 2004 transit to test alot of devices and technologies that Kepler and future missions will use.

The most important one was done by ACRIM which showed a orbiting spacecraft CAN detect a minute drop (about 0.1%) in a parent star's (the Sun!) light reaching a detector.

Good news though: There will be another transit on June 6, 2012. I bet this will be used as well!

Posted by: antoniseb May 22 2006, 07:02 PM

It seems to me that many more opportunities happen than this. We need only look at the light curve of medium to large asteroids as the Earth, or Venus, or Mars, or Jupiter transit the Sun from their locations. There must be dozens of such events per year. More if you want to look at smaller objects.

Posted by: BruceMoomaw May 23 2006, 01:59 AM

I believe that they do intend to get a lot of data on star variability as a fringe benefit from the Kepler mission -- just as ESA's cancelled Eddington mission would have done the same two things, but in reverse order of priority.

By the way, one selling point for the proposed "Joint Dark Energy Mission" that NASA and the Dept. of Energy were planning to team up on as the first "Beyond Einstein" mission -- although those have been put on indefinite hold due to the serious funding problems in NASA's Astrophysics Division -- was that, by adding just $100 million to its total cost, it could follow up its initial measurements of very distant supernovas with a very extensive microlensing census of planets in one of the Magellanic Clouds.

Posted by: PhilHorzempa May 23 2006, 03:57 AM

Here is a direct look at Kepler's FOV (Field of View).

Kepler will be staring at this FOV for 4 years, looking for transits. In this FOV,
there are about 200,000 stars, half of which will meet the criteria for planetary
search (single, non-variable, etc.).

Therefore, Kepler will be sorting through the brightness stability of about
100,000 stars. I think that it would add immensely to one's appreciation of
the magnitude of Kepler's mission if there were actual images of the galactic
star fields inserted into the FOV above.

In fact, it would be helpful to have high-res digital images of each of the
21 sub-fields (each of these sub-fields will be covered by one of Kepler's CCD's).


Does anyone have access to a good source of Milky Way digital imagery,
especially of the area near Cygnus, shown above?


Another Phil

Posted by: ljk4-1 May 23 2006, 03:10 PM

Systems Engineering for the Kepler Mission

http://kepler.nasa.gov/pdf_files/SPIE.Glasgow.Duren.pdf

Posted by: PhilHorzempa Jul 1 2006, 03:42 AM

Here is an image of a Milky Way star field in the vicinity of
Alpha Cygni (Deneb).

http://video.library.gatech.edu/Barnard_Project_W/plate/Bar-pt1-pl045_sm.jpg


This image is near the Kepler FOV and gives an idea of the task facing
Kepler. Recall that Kepler will be staring at a star field, containing
about 100,000 - 200,000 stars, for 4 years looking for planetary transits.
This image is part of an on-line collection of classic Milky Way
images obtained by E.E. Barnard. The search page can be found at

http://video.library.gatech.edu/cgi-bin/bpdi/search.pl?search=0



Another Phil

Posted by: AlexBlackwell Feb 7 2007, 04:49 PM

http://www.space.com/businesstechnology/070207_kepler_mission.html
By Leonard David
Senior Space Writer, Space.com
posted: 07 February 2007
06:27 am ET

Posted by: ustrax Jul 16 2007, 03:18 PM

http://www.space.com/spacenews/070716_businessmonday_kepler.html

Posted by: djellison Jul 16 2007, 03:26 PM

"There's a new team in town and we don't work that way"

I think we should club together and buy Alan a sherif badge

All credit to the guy - these are not easy decisions to make - and the best decision is rarely the easiest one.

Doug

Posted by: Greg Hullender Jul 16 2007, 03:26 PM

I really love the Kepler mission concept, and I've been sad to see it delayed so long, but (reading the article) it sure sounds like Alan was spot-on with this one. Sadly, it feeds my perception that most of Nasa's problems are self-inflicted. On the bright side, it suggests things could get much better if Alan keeps making calls like this.

--Greg

Posted by: ustrax Jul 16 2007, 03:45 PM

...

Posted by: Jim from NSF.com Jul 16 2007, 05:08 PM

Why this so different from the first Dawn decision?

Posted by: hendric Jul 17 2007, 12:33 PM

Too bad Alan wasn't around to prevent the GP-B fiasco.

Slightly related...We've often heard the quote, "That sure would look great in the Smithsonian". Got two questions:

1. Are there any projects that were killed and placed in the Smithsonian, or A&S museums in general?

2. Really, wouldn't you be disappointed to see an unlaunched space probe sitting there in the A&S museum? I think it would be better to mount it in the foyer of the managing team's facility as a reminder.

Posted by: djellison Jul 17 2007, 12:51 PM

Two examples - one big, one small.

The Saturn V at JSC is built from parts destined for Apollo 18/19 and/or the third stage that got pulled off to make room for Skylab.

And Marie Curie - the Sojourner spare - then destined for the 01 lander, which got cancelled, and never made it onto the Phoenix payload - not sure where she lives now but she's been to exhibitions afaik.

Doug

Posted by: Jim from NSF.com Jul 17 2007, 03:18 PM

Back up Skylab,
Agena
Triana is some where
AFP-888, P80-1, Teal Ruby

Posted by: edstrick Jul 18 2007, 06:12 AM

"...The Saturn V at JSC is built from parts destined for Apollo 18/19 and/or the third stage that got pulled off to make room for Skylab..."

I believe there are 3 Saturn 5's on display, the third one at Marshall or somewhere Huntsville, though only 2 flight vehicles remained after Apollo's 18 and 19 were budget canceled. The third vehicle is the dummy pad-checkout vehicle that was used to test VAB/Crawler/Pad operations and connections/hookups before Apollo 4's Saturn 501 was prepared for launch. I read somewhere that parts of it are included in both the Canaveral and Houston display vehicles, so none of the vehicles on display is 100% flight capable hardware.

Posted by: djellison Jul 18 2007, 11:26 AM

This is what Wiki says:

Currently there are three Saturn Vs on display, all displayed horizontally:
A Saturn V on display at the U.S. Space & Rocket Center in Huntsville, Alabama.
A Saturn V on display at the U.S. Space & Rocket Center in Huntsville, Alabama.

* At the Johnson Space Center made up of first stage of SA-514, the second stage from SA-515 and the third stage from SA-513.
* At the Kennedy Space Center made up of S-IC-T (test stage) and the second and third stages from SA-514.
* At the U.S. Space & Rocket Center, made up of S-IC-D, S-II-F/D and S-IVB-D (all test stages not meant for actual flight)(soon to be moved to a new visitor's center).


So the JSC one is all flight hardware (and the only one to be so) - just not from the same vehicle.

Posted by: stevesliva Jul 18 2007, 03:46 PM

The space station appears destined to contribute a lot of hardware to these lists.

Posted by: Jim from NSF.com Jul 18 2007, 08:10 PM

Only 3 MPLM's
the rest wasn't built

Posted by: PhilCo126 Aug 31 2007, 06:46 PM

In which parts of the Electromagnetic spectrum are Kepler's detectors active ( Visible and Infrared ? )

Posted by: AlexBlackwell Aug 31 2007, 06:56 PM

From the http://kepler.nasa.gov/sci/design/spacecraft.html: "The [photometer] has a spectral bandpass from 400 nm to 850 nm."

Posted by: PhilCo126 Sep 8 2007, 01:05 PM

Kepler mission: Work in progress
http://www.ballaerospace.com/gallery/kepler/

Posted by: Del Palmer May 5 2008, 06:51 PM

Just finished submitting your name for LRO? Now send it on Kepler!

http://www.seti.org/kepler/names/

Posted by: GravityWaves Jun 14 2008, 04:12 PM

Kepler is expected to be able to discover at least 50 earth sized planets

Posted by: Greg Hullender Sep 27 2008, 06:27 PM

Another Kepler update.

http://www.jpl.nasa.gov/news/news.cfm?release=2008-179

The spacecraft is in Colorado and survived the termal vacuum test. I note they're only saying it'll launch in 2009 -- I wonder if they have quietly backed off the April 2009 date. Anyway, NASA elsewhere still shows an April 10 launch date.

http://www.nasa.gov/missions/highlights/schedule.html

--Greg

Posted by: Greg Hullender Oct 8 2008, 05:04 PM

They're now showing Kepler scheduled for launch: 2009 March 4, 10:46 pm EST on the Kepler web site.

http://www.kepler.arc.nasa.gov/

Still no countdown though. :-)

--Greg

Posted by: Ron Hobbs Oct 11 2008, 08:04 PM

The NASA Launch Schedule now has the Kepler launch set for April 10.

http://www.nasa.gov/missions/highlights/schedule.html

Posted by: Ron Hobbs Oct 15 2008, 04:06 PM

Yesterday, NASA moved the launch of Kepler back to "no earlier than" March 5. They do not list a launch time.

Posted by: BPCooper Feb 21 2009, 07:56 PM

I haven't seen any posts on Kepler in a while and with the launch less than two weeks off I figured I might post :-)

The Kepler observatory made the 20 mile trip from the Astrotech cleanroom to LC-17B Thursday morning and after a couple days of delay due to weather was this morning lifted and mounted atop the 13-story Delta 2 rocket that will take it into space in 12 days. Some http://www.launchphotography.com/Kepler_cleanroom.html from the media viewing a few weeks ago.

Launch is on target for Thursday March 5 at 10:48pm EST. There will be two launch windows of exactly three minutes each that day, stretching from 10:48:43 - 10:51:43pm and 11:16:34 - 11:19:34pm EST. NASA TV coverage begins at about 8pm or 8:30pm; www.nasa.gov/ntv.

Posted by: helvick Feb 22 2009, 01:11 AM

Thanks for the update Ben - much appreciated.

Slightly OT but I'm curious about how much time you have to spend just hanging about waiting for launches to get windows defined with a confidence level that enables you to get all your kit prepared for setting up - basically do you end up having to sacrifice weeks\months of time in order to be sure of getting a shot or are you able to actually work a more or less normal life around launch windows?

Posted by: Byran Feb 26 2009, 06:44 PM

I hope that Kepler would have to wait for the results is less than Corot.

http://www.kepler.arc.nasa.gov/pdf_files/314125main_Kepler_presskit_2-19_smfile.pdf

Posted by: Stu Feb 26 2009, 07:03 PM

Thanks for the link to the Kepler info Byran, fascinating stuff, but there's not a lot of point copying a great chunk of it - or other reports, etc - into your post too. Best to let people follow the link and read it for themselves if they want to.

Posted by: Greg Hullender Feb 26 2009, 11:11 PM

Although I think this bit is worth posting, since it answers the question of "how long must we wait for results?"

"The first planets discovered by Kepler will be gas giants, similar in size to Jupiter, in close orbits lasting only a few days around their parent stars. Planets in Mercury-like orbits with orbital periods of only a few months will be discovered using data from the first year of operations. Finding Earth-size planets in Earth-like orbits will require the entire length of the 3.5-year Kepler Mission."

If I recall correctly, the reason it takes as long as it does is that they need to see the planet transit three times; once to discover it, a second time to get the period, and the third time to confirm the result.

--Greg

Posted by: kwan3217 Feb 27 2009, 07:28 PM

Launch has been pushed back a day to check the Delta II for any common parts with the Taurus that failed this week. Launch now no earlier than Friday, 6 Mar 2009 at 10:49:57 p.m. EST (Saturday 7 Mar 2009 03:49:57 UTC)

http://spaceflightnow.com/delta/d339/status.html

Posted by: BPCooper Mar 3 2009, 12:52 AM

The Delta 2 rocket with Kepler has been cleared for blastoff Friday night at 10:49pm. There is a 90% chance of acceptable weather conditions predicted.

http://spaceflightnow.com/delta/d339/status.html

Posted by: imipak Mar 3 2009, 08:59 PM

*ulp*. This is the most nervous I'm going to be until the MSL launch / EDL. (Of couse, with Kepler the launch is "easy" bit... )

Posted by: ustrax Mar 4 2009, 09:57 AM

imipak, Kepler and its possibilites is definitily a mission that fits in my "special cookie" condition...what will it find? What surprises expect us? A legion of earth-like planets or the absence of these? Either way it will have a huge impact in the future not only in space exploration but mostly, in my opinion, in our perspective towards the place we occupy in the universe. It will, surely, open our eyes and pave the way to a different reality. Truly a revolutionary mission for a species like ours...therefore here I am, with this strange, good feeling in the stomach, all excited, all nervous and crossing my fingers. Probably the launch I am following with more anticipation...Friday will be a great day...

Posted by: imipak Mar 4 2009, 08:01 PM

I hope, _hope_, /HOPE!/ that you're right. Until Kepler's safely in orbit without mishap, though, I can't think of those as anything but potential possibilities. I'm a devout rationalist, but events like this really help me understand why, and how, superstitions develop. Pucker factor: 0.4...

I'm trying to persuade a colleague at work with a latent interest in UMSF to wake his kids up to watch the launch. He expresses what he thinks is a rational aversion to spending money on U?MSF in general, but I can tell he secretly digs the "cool" factor. I'm guessing his kids are his weak point!

Posted by: ustrax Mar 4 2009, 08:09 PM

And how cool can it get the fact of watching the launch of a mission that has the potential to change the way we see the Universe?
I would like to tell my grandchildren that I was there watching the launch of Kepler, the one who first sighted a-n-o-t-h-e-r earth, but hey...we're all talking about in the hypothetical field here...man...why does friday take so long to arrive?

Posted by: imipak Mar 4 2009, 08:53 PM

I'm sure there's a Portuguese equivalent of the English expression: "A watched pot never boils" ... *grin*

Posted by: ustrax Mar 4 2009, 09:30 PM

Yes, I know the expression...I have chosen another one for the occasion...
Barco parado não faz viagem.
Tictactictactictac....

Posted by: PhilCo126 Mar 5 2009, 08:42 AM

Did anyone found a weblink with the dimensions of the 1040 kilograms Kepler Space Observatory?

Posted by: ustrax Mar 5 2009, 11:18 AM

Nope...I would say 5 to 6 meters tall...
Only found the info at the mission site, with the photometer dimensions it is just a question of doing the maths...
http://kepler.nasa.gov/sci/design/spacecraft.html

BTW, http://beyondthecradle.wordpress.com/, spacEurope's sucessor, is welcoming some members of the Kepler team, the last one was Alan Gould, here's a bit of it, revealing how this guys imagination is running wild...gotta love science... :

"We just finished 2 days of very exciting Kepler Science Team meetings here in Cocoa Beach FL (Mon-Tue, Mar 2-3), getting ready for Friday’s launch. We’re all extremely suspenseful, elated, and hopeful all at the same time. The science discussions were fascinating and intriguing–some about all the different types of transits we might observe with different classes of stars, different sizes of planets, shapes and periods of orbits, planets orbiting eclipsing binary stars, all stimulating thoughts of strange and wonderful new worlds."

If you scroll down you will also find a piece by Edna DeVore...everything that helps passing the time is welcome...

Posted by: PhilCo126 Mar 5 2009, 03:21 PM

Ben Cooper Launchphotography has amazing photos of the Kepler Space Observatory:
http://www.launchphotography.com/Kepler_cleanroom.html


for spacecraft dimensions: google --> Kepler Press Kit

Posted by: Greg Hullender Mar 5 2009, 04:59 PM

I have a "no peanuts" rule this time, though . . .

--Greg :-)

Posted by: ustrax Mar 5 2009, 05:25 PM

If my time zone doesn't fail me there will be within 30 minutes (1 p.m. EST) a Kepler Mission Pre-Launch Science Briefing at NASATV.

EDITED: Speaking of hours help me here (it's always the same thing with every event...), the launch will take place in my GMT time on Saturday 03:49:57AM? Correct? Or not?...

EDITED: Stu just made me a very happy man...
http://countdown.ksc.nasa.gov/elv/

Posted by: Vultur Mar 6 2009, 11:33 AM

16 hours left...

fingers crossed...

Posted by: ugordan Mar 6 2009, 12:02 PM

Relax. Those guys are pros.

Posted by: ustrax Mar 6 2009, 12:42 PM

Great to see the attention it is getting on CNN's website...top story!

Posted by: SpaceListener Mar 6 2009, 02:43 PM

I am trying to find out about the future position of Kepler with respect to Earth. So far I have found the following info which does not satisfy me since it does not tell me about how far will be Kelper following up to Earth with a constant distance?

Posted by: remcook Mar 6 2009, 02:56 PM

My impression was that it would move further and further away from Earth.
Google is very useful:
http://redorbit.com/images/gallery/kepler/keplers_earth_trailing_orbit_around_the_sun/163/41/index.html

Posted by: HughFromAlice Mar 6 2009, 03:40 PM

I went here http://kepler.nasa.gov/sci/design/orbit.html

NASA press kit is interesting - orbit info on page 14 http://www.nasa.gov/pdf/314125main_Kepler_presskit_2-19_smfile.pdf

Kepler needs uninterrupted viewing to ensure most efficient use of observation time for planetary transits ("100,000 stars will be monitored continuously and simultaneously")!!!!! - therefore it is being put into a heliocentric orbit that trails behind the earth where earth/moon will not block the view. Also important - being further away from effects of things like earth/moon gravity, magnetoshpere etc means good stability and so better pics. Kepler's orbit will gradually fall further behind the Earth (worst case 0.5 AU after 4 years) but it will still be within communications range even after the end of the nominal mission - 3.5 years. Will probably get funding a bit longer after that.

Hope this helps.

Posted by: SpaceListener Mar 6 2009, 05:18 PM

Thank you HughFromAlice. Its heliocentric orbit takes 371 days means that it will be keeping away from Earth in every year until it will meet again with Earth in very far future.

Posted by: ustrax Mar 6 2009, 11:10 PM

Man...Jon Jenkins back at http://beyondthecradle.wordpress.com/ contagiated me with is emotions...if I was intending to stay calm I can't avoid to become all emotional...

"I’ve been waiting for this moment for 14 years. Tonight, NASA Discovery Program’s Kepler Mission will blast off at 10:48 pm from Canaveral Air Force Station taking the hopes and dreams of myself and so many other people who’ve worked so hard for so long to make this moment happen. It feels like I’m on a roller coaster on its way up to the first big hill, ka-ching, ka-ching. I can just start to see the big drop just beyond the crest of the tracks, and at launch there will be no turning back and we’ll be taken along for one of the most thrilling rides of our lives. Yesterday I watched “Magnificent Desolation” at the IMAX theater at KSC Visitor Complex. Unbidden tears formed in my eyes and flowed down my cheeks towards the end of the film. The enormity of the goals and aspirations achieved by the Apollo Program are overwhelming."

Posted by: nprev Mar 7 2009, 12:26 AM

Great, moving words. I think all of us are pretty excited, but I can only imagine how the team members feel right now.

GO KEPLER!!!!!

Posted by: Zvezdichko Mar 7 2009, 06:07 AM

Looks like launch was successful.

Posted by: eoincampbell Mar 7 2009, 07:26 AM

Brilliant launch Kepler, (I'm Ecstatic)
Go Find 'Em
Flea on the Headlight!

Posted by: PhilCo126 Mar 7 2009, 07:59 AM

Indeed, together with CoRoT a very interesting mission to look forward to...
BIS Spaceflight May 2009 will have an article on Kepler

Posted by: Stu Mar 7 2009, 01:24 PM

Gorgeous launch pics by Ben Cooper...

http://www.launchphotography.com/Kepler.html

Second one is an absolute beauty, Ben, well done!

Posted by: FrankB Mar 7 2009, 01:24 PM

I don't know about Corot... It seems it didn't gone so well with planets detections There is a new article here: http://www.cnes.fr/web/CNES-fr/7492-jour-de-chance.php
I tried to translate it with google and I am pretty disapointed:

To date, 7 CoRoT exoplanet discovered with certainty, including the smallest ever detected. This is an array of hunting already significant, but it is actually far less than what the researchers expected to discover. "We are half the planets as we had hoped" said Peter Barge. "We were so intrigued that we first thought there was a problem in detection methods. We distributed to all teams of the light curves with simulated transits to see if it was the methods of signal processing that were reviewed. But all the simulated planets had been identified ... " Another hypothesis, that of a noise, a disturbance signal which would be higher for low-light stars, often longer. "We will soon be able to better filter the residual instrumental noise on the low stars. We will see then if we find the planets expected. » " But if no new planet revealed the tip of the eclipse, it should be made to face the facts: the problem will not come from the instrument, but the stars themselves. "Maybe the planets are formed preferentially in our little galaxy" advance Pierre Barge with a smile. "Maybe the planets are formed preferentially in our little galaxy" advance Pierre Barge with a smile. The Sun and its retinue of planets and that a majority of the exoplanets detected are located in one arm of the galaxy, the Orion arm, a fairly dense area that could be more conducive to the formation of planets and other regions. But for now, this is still a hypothesis, "says the researcher.

Posted by: dmuller Mar 7 2009, 01:57 PM

Does anybody know where I can find the spice kernels for Kepler? Since it's orbiting the Sun, I would want to include it on my site.

It will slowly fall behind Earth as it goes around the Sun ... Kepler orbits the Sun and not Earth. To keep it at a constant distance from Earth would involve at least two major trajectory correction maneuvers, so it is much more efficient to launch it into an orbit which is similar to that of Earth

Posted by: SpaceListener Mar 7 2009, 03:19 PM

I am glad to know that the launch of Kepler was stunning and succesfull in spite of the fact that there were minor problems with some delay of relaying data to space center.

Posted by: BrianJ Mar 7 2009, 07:45 PM

Congratulations on a succesful launch to everyone involved with the Kepler mission.

I have two questions which someone here may be able to enlighten me on:

1. Why wasn't an L2 orbit used (similar to the forthcoming Herschel and Planck missions)? Wouldn't an L2 orbit give a longer mission lifetime?

2. If/when an exo-planet is detected, is there any way to determine the eccentricity of it's orbit (either by Kepler or by ground based observations)?

Best regards,
Brian

Posted by: scalbers Mar 7 2009, 08:28 PM

Yes, the radial velocity method can determine the eccentricity...

Posted by: belleraphon1 Mar 7 2009, 09:28 PM

Congratulations to the mission launch team on this beautiful launch. Heart was in my mouth waiting for confirmation of Goldstone signal.

In 1991, when the pulsar planets were announced, we started writing the Book of ExoWorlds. How many pages will be added in 4 years time?

KEPLER (and COROT) will answer a question I have been wanting an answer to ever since I was old enough to understand the question. How common are Earth sized planets?

As Alan Boss has noted, we are entering the platinum age of explanetary science.

Craig

Posted by: BrianJ Mar 7 2009, 09:56 PM

Using spectroscopy/doppler shift measurements? That's possible for Earth-sized planets? Even if there's a Jupiter-sized planet in the same system(messing things up)? Wow.

I think I'll have to try to crunch some numbers on that, to get my head around it.

The more I think about it, the more amazing the process of making those measurements, and disentangling them, becomes.

Thanks.

Posted by: Del Palmer Mar 8 2009, 01:49 AM

I recall L2 being mentioned early on, but they descoped along the way in order to fit on a Delta II -- it's sobering to think Kepler was rejected four times before being accepted!

Posted by: MahFL Mar 8 2009, 02:59 AM

We saw the launch last night in real life from our location in Orange Park, FL. The Delta 2 looked like a large firework rocket at first. Then an orange light which noticeably accelerated. We have seen the Shuttle launch several times and also I think one of the Rovers.

Posted by: tasp Mar 8 2009, 03:34 AM

It would not be confirmable by the 3 observation criteria, but it would still be interesting to review Kepler light curve data for brightenings possibly due to equivalents of Kreutz sun grazers. (IIRC, some Kreutz sun grazers have been visually observed in daytime near the sun, implying a summed magnitude increase greater than the expected decrease in magnitude due to a planetary type stellar transit)

Posted by: nprev Mar 8 2009, 06:24 AM

Considering that the Kreutz group is thought to have originated from the breakup of a single large object perhaps less than a thousand years ago, and that a comet's peak brightness during periastron lasts only a few days at most, I think detection of such events by Kepler are statistically unlikely in the extreme.

Posted by: scalbers Mar 8 2009, 03:06 PM

Well I should qualify that the radial velocity method generally works for planets larger than the Earth, depending on how close they are to their parent star. I've heard radial velocity limits between .3 and 3 m/s that would depend on the brightnesss of the parent star.

http://kepler.nasa.gov/sci/capabilities.html

It can determine the eccentricity though as well as work with multiple planets to disentangle the individual signals.

Posted by: scalbers Mar 8 2009, 03:10 PM

Perhaps though the light curves of the asteroids would be more influenced by their rotation compared with a star?

Posted by: climber Mar 8 2009, 04:11 PM

Opportunity was launched at night.
An watch out next wednesday you'll enjoy Discovery's night launch too.
Lucky man.

Posted by: BrianJ Mar 8 2009, 06:11 PM

Thanks Del. I'm certainly glad Kepler made the cut in the end!

Some back-of-the-envelope calculations tell me that Kepler has a max. dV of ~23m/s (assuming 12kg propellant, ISP 2000Ns/kg)
From what I can find out on the web, Herschel(direct injection to L2 halo orbit) will need ~200m/s dV (inc. safety margin). So Kepler would require ~90kg of extra propellant on board to match that.

The largest component of the Herschel dV budget seems to be for correction of launcher error. So I guess it's largely down to the accuracy required for a launch to L2 halo orbit (compared to a launch to Earth-trailing heliocentric orbit).

@scalbers: Thanks so much for the link to the Kepler/Planet Detection Methods page. That makes the limitations of the different methods quite clear. I was just wondering if a system similar to the Earth/Sun were detected, could we tell whether it was a "habitable" place (low eccentricity) or being alternately roasted and frozen every orbit (high eccentricity).

Best regards,
Brian

Posted by: Mongo Mar 8 2009, 07:53 PM

It would be possible to determine that a particular planet had a high-eccentricity orbit using only transit information (under certain viewing circumstances), but many high-eccentricity planets would not be recognized as such.

The time between successive planetary transits (combined with the primary star's estimated mass) determines the semi-major axis, while the total duration of the transit from first to last contact is determined by the "impact factor" (how central the transit is, relative to the stellar disk), the diameter of the stellar primary and the velocity of the planet while transiting in front of the star. So if the stellar parameters are reasonably well-known, a transit duration longer than that expected from a central transit of a low-eccentricity planet says that the planet must be slower (and hence farther from its primary) at that moment than expected at any time in a low-eccentricity orbit, and so its eccentricity must be high.

However, a transit duration less than the expected duration of a central transit and a low-eccentricity orbit means little, since the transit might be off-center or grazing, which would reduce its duration as well.

Posted by: Syrinx Mar 8 2009, 08:00 PM

I made it out to the Kepler launch party here at NASA Ames in Mountain View, CA. After the launch, masses of people starting filing out and I was able to grab a few minutes with Dr. Tom Roellig, co-investigator for Kepler. There were a few of us pelting him with questions, some of them interesting.

- "Flea on a headlight" whatever, what's the intensity resolution? Kepler has 16-bit A2Ds.

- Kepler has an 90 megapixel digital camera. Is all that data beamed back to Earth? No, just the pixels that have a star sitting on them, about 5%. Then compression is about 2:1.

- Does a star move from pixel to pixel during measurements? No. A star will sit within one pixel with a LARGE amount of the pixel to spare.

- What if a star just happens to be right on the border of one pixel and another pixel? Kepler blurs adjacent pixels to account for this. (Not clear to me if this is accomplished in software or hardware.)

- Why is Kepler's life span just six years? Not enough fuel. Have to desaturate from time to time, no choice.

- (My question) Can we expect preliminary data to be published in May or June? Yes and no. The Kepler team will have some data and preliminary "subjects of interest" but they won't publish it. Because some media will misrepresent the data and you'll have headlines such as "30 Earths found!!!" and NASA will look bad for no reason when NASA has to clean up the mess.

Posted by: scalbers Mar 8 2009, 08:53 PM

Perhaps in principle a transit can be determined to be off-center if we time the steepness of the light curve's descent/ascent. I'm unsure though that Kepler would have the requisite time resolution.

Brian, it looks like an Earth-Sun analogue would have a few times less radial velocity than would be needed, though one might get close if the star was near and bright with lots of photons.

Syrinx, I was at a similar launch party at CU/LASP where the mission is being controlled from. I gather most of the science activity will be at Ames.

Posted by: dilo Mar 8 2009, 09:09 PM

Syrinx, my understanding is that star images are deliberately unfocused at sensor and their blurred images are about 7 pixel wide. This "hardware blur" offers many advantages in terms of precison and dynamic range because it reduces effect of different pixel responses and avoid fast saturation...
Take in mind that Kepler camera is not used to took real pictures ( ) but only extremely accurate photometry of selected stars in the field.

Posted by: robspace54 Mar 10 2009, 05:18 PM

I am an engineer for MAG Cincinnati (formerly Cincinnati Machine) and we built a large vertical milling machine which was used as a grinder to grind the 1.4 meter diameter photometer mirror for Kepler. The U5 machine was built for L-3 Communications (Brashear) who performed the work for NASA.

So I say bon voyage to Kepler and use your mirror well! Catch a few Earth-sized objects!!!

Rob

Posted by: PhilCo126 Mar 10 2009, 06:33 PM

Talking about mission life time; there was already talk of a possible extension to six years, which would allow improved observations of more transits to detect smaller planets and of course finding planets in larger period orbits

Meanwhile:
http://www.astronomynow.com/090310KeckandKeplertojoinforces.html

Posted by: HughFromAlice Mar 10 2009, 10:39 PM

Ref the article: Interesting!!! Especially ..... "Furthermore, Marcy and his team can use the Keck-calculated mass and Kepler-calculated diameter to determine the planet's density". (My bolding)

Posted by: Hungry4info Mar 10 2009, 10:46 PM

I am unsure why you bring attention to this. Density = mass / volume, with the mass and volume of a planet, we can calculate its density fairly easily. The density of transiting planets is not unmeasured.
To name a few examples:
HD 209458 b -> ~ 0.41 g cm^-3.
HD 149026 b -> ~ 0.82 g cm^-3.
HAT-P-2 b -> ~11.9 g cm^-3.
HD 189733 b -> ~ 1.06 g cm^-3.
TrES-3 b -> ~ 0.99 g cm^-3.

And so on...

Posted by: AndyG Mar 11 2009, 09:32 AM

Denser than lead? That - Jovian cores aside - doesn't seem very planet-like to me.

Andy

Posted by: HughFromAlice Mar 11 2009, 10:57 AM

As I understand it (being an interested amateur) the radius of planets can only be determined from the shape of their light curves using transiting techniques. Since Kepler will be in space and has such an advanced photometer, it will be able to determine the size of planets that are even smaller than Earth. It will simultaneously observe a huge number of stars - 100,000.

Before reading the article I didn't realize that there was any radial velocity technique sensitive enough to check out the mass of such small planets. Since Keck has the capability to detect changes in radial velocity down to below 1/m sec, it is senstive enough. It will target the transit positives.

So you were right to comment!!! Currently we only know the size and and mass of a small percentage of planets - the new Planetary Society exoplanet catalogue is really useful resource. What I should have said was ...... density of (hopefully a lot of) earth like planets!!!. That's exciting. How many will be around the 5.75 gm/cc? I believe radial velocity techniques currently only estimate min mass with + ~20% error range to more heavy than estimated - worse if not in line of site.

PS - Andy - TPS catalogue gives HAT-P-2 b density ~13.37 gm/cc!! 'Super Earth' CoRoT-Exo-7b density ~11.36 gm/cc!!

Posted by: SpaceListener Mar 11 2009, 02:22 PM

That has brought to my attention. How does the team determine its mass?
Using the mass spectometry determines it? If it is so, which of the following
method uses:

a) Vaporisation
'b)' Ionisation
c) Acceleration
d) Deflection
e) Detection


Regards,

Posted by: dilo Mar 11 2009, 03:50 PM

SpaceListener, I hope you're jocking...
If you are able to put an exoplanet inside a mass spectrometer, you are a genius!

Posted by: djellison Mar 11 2009, 05:11 PM

I assume by the scale of it's influence on the parent star.

Doug

Posted by: PhilCo126 Mar 12 2009, 08:58 AM

Correct Doug... examining the star's (periodic) radial velocity(ies) reveals the mass(es) of exo-planet(s).

AdyG --> http://en.wikipedia.org/wiki/HAT-P-2b

Multiple exo-planets:

Posted by: siravan Mar 12 2009, 11:23 AM

Using radial velocity technique, one can calculate m.sin(i), where m is the mass and i the orbital inclination (for one or more planets). Hence, the radial velocity only determines a lower limit on the mass. If an exoplanet is observed by both radial velocity and transit method, it means i=90 (due to seeing a transit), and that fixed the mass. Planet radius can be calculated by transit method. Therefore, using a combination of radial velocity and transit methods, it is possible to calculate the density (but neither does it alone).

Posted by: Mongo Mar 12 2009, 02:48 PM

One unexpected (to me) fact is that using a planet's transit light curve and its primary's spectroscopic orbit (radial velocity), one can calculate the planet's surface gravity directly, as opposed to indirectly via mass and radius. This was discussed in http://www.unmannedspaceflight.com/index.php?showtopic=4102& from a couple of years ago.

Posted by: Vultur Mar 12 2009, 07:58 PM

When will Kepler begin to actually observe stars?

Posted by: Mongo Mar 12 2009, 08:05 PM

According to the http://twitter.com/NASAKepler, it will be another 50-60 days before science operations start, so early to mid May.

Posted by: Stu Mar 12 2009, 10:27 PM

Anyone wanting to read some background info about - and comments from people involved in - the Kepler mission should check out Ustrax's new blog, Beyond The Cradle. Some really good stuff on there, written by one of our most passionate and enthusiastic members. He's also been kind enough to use my latest poem, which was inspired by Kepler's mission.

http://beyondthecradle.wordpress.com

Posted by: ustrax Mar 12 2009, 11:17 PM

You're too kind my collab...friend...

Vultur and Mongo, Natalie Batalha told me that the next crucial event will be to eject the dust cover, that's when Kepler will get its first-light image, this will take place two weeks from now, on the 26th...that also when Batalha's will make her appearance at the blog...

Posted by: ngunn Mar 12 2009, 11:33 PM

A well-deserved plug. I'm on board for Rui's mission.

While we're at it, don't miss Stu's Kepler piece at Cumbrian Sky.

Posted by: PhilCo126 Mar 13 2009, 10:11 AM

I'll second that... superb blog Ustrax !!! ( ... something completely different ).
Did I understand correct that the photometer was already turned on for tests, but the dust cover will stay on another fortnight?

Posted by: ustrax Mar 13 2009, 10:50 AM

Thanks, having Stu on the crew makes it worth of a visit...
If you have any suggestions please feel free to e-mail be about it...

Phillipe, I don't know about the photometer being already turned on, it's possible, I'll try to check it today, but, for sure, the first light won't be acquired before the 26th, that's when the cover gets ejected.

Posted by: Syrinx Mar 13 2009, 06:03 PM

Thw twitter feed states that the photometer was switched on for testing on March 9th.

Also says the cover is still on.

Posted by: HughFromAlice Mar 14 2009, 10:01 PM

Testing: The complexity of modern spacecraft is amazing. Glad they're testing! For instance, the detector electronics box which turns analog signals from the CCDs into digital data has more than 22,000 electronic components.

Posted by: Stu Mar 15 2009, 12:22 PM

Planning on incorporating Kepler's mission into two Outreach talks next week, but struggling to find a good all-sky star chart showing which stars have exoplanets. Can anyone help out?

Posted by: Hungry4info Mar 15 2009, 04:51 PM

The closest thing to that I can think of is a script I have in Celestia which marks the positions of known extrasolar planetary systems. But ... Celestia isn't the best tool for making all-sky star charts. I can probably make you an all-sky star chart showing the positions of exoplanets if you give me an hour or so.

All I'll need is a blank all-sky atlas.
Edit: Found one.

Posted by: Greg Hullender Mar 15 2009, 05:58 PM

Interesting question.

The Exoplanets Forum might be a good place to ask: http://listes.obs.ujf-grenoble.fr/wws

NASA's Planetquest site has some sort of 3d "New Worlds Atlas" but I can't get it to work in my browser.

http://planetquest1.jpl.nasa.gov/atlas/atlas_index.cfm

The exoplanets encyclopedia has a list of astronomers and groups working in the area. You could consider spamming all of them:

http://exoplanet.eu/people.html

(Or maybe just the groups -- there are a LOT of individuals!)

This table has the raw data (in the format of your choice), so you could plot it yourself, if you wanted to:

http://exoplanet.eu/catalog-all.php?mdAff=output#tc

And this site claims to be able to do interactive visualizations, although I couldn't see how to do more than query their database. You could ask, though:

http://nsted.ipac.caltech.edu/NStED/docs/holdings.html

Probably that's not better than what you found in your own web search, but I hope it helps.

--Greg

Posted by: Hungry4info Mar 16 2009, 12:36 AM

I looked at the 3d worlds atlas at the Planet Quest site, and I discovered that it could not produce what was needed. It shows a 3d model of the solar neighborhood. Only stars with planets are included though.

Posted by: dmuller Mar 16 2009, 06:04 AM

Early release version of the Kepler realtime simulation is now online at http://www.dmuller.net/kepler

Posted by: PhilCo126 Mar 16 2009, 10:17 AM

Interesting to find out where & when the Kepler Space Observatory will be "visible" from Your location:
http://ssd.jpl.nasa.gov/horizons.cgi
enter: Kepler (Spacecraft) as Target Body
and You'll find out the spacecraft is in constellation LEO MINOR

Posted by: ustrax Mar 16 2009, 10:24 AM

If you guys have any question regarding the mission Jon Jenkins, one of the Co-Investigators, will be happy to answer it at Beyond the Cradle until March 26.
Here's the http://beyondthecradle.wordpress.com/2009/03/16/kepler-mission-anticipating-first-light/.

Posted by: PhilCo126 Mar 17 2009, 08:37 AM

http://astronomynow.com/090309DavidKochInterview.html

Posted by: Stu Mar 20 2009, 06:44 AM

re. an all sky map of exoplanet locations...

What an idiot I am! The answer was obvious and staring me in the face - Google Sky! I found a great website that has, among other things, a layer showing the locations of exoplanets ( http://stellarcartography.blogspot.com/2007/08/sky-in-google-earth.html ) and it works perfectly!

Well, I say "perfectly"... actually my computer is so old that it struggles with GoogleAnything; the video card is so prehistoric that it is no longer supported by its manufacturer, and the display of Google Mars/Earth/Sky freezes after a few minutes. So I'm "mapping" the exoplanet sky a few small chunks at a time, building up an atlas which will be really useful. A new computer is planned for later this year, then I'll be able to enjoy strolling around Mars like other people here.

Posted by: PhilCo126 Mar 20 2009, 11:01 AM

Thanks for pointing out this blog Stu
Hope You'll have a new computer very soon...

Posted by: Stu Mar 21 2009, 05:07 PM

Some very useful Kepler- and exoplanet-related downloadable Outreach resources here...

http://kepler.nasa.gov/ed/starwheel/index.html

Posted by: ustrax Mar 23 2009, 12:06 PM

The answers to the great questions that some of you guys sent to Jon Jenkins are alreasdy posted at BtC.
Here's the http://beyondthecradle.wordpress.com/2009/03/23/kepler-mission-anticipating-first-light-the-answering-post/.

Posted by: ustrax Mar 24 2009, 08:31 PM

Just got word from Natalie Batalha saying that there will be a slight delay, a couple of days, on the detection of first light.

Posted by: Syrinx Mar 25 2009, 07:00 AM

By my count, the shutter was to be thrown overboard on March 25th (basically today). I'm wondering if the shutter will still be opened today (with Kepler's optics disabled), or remain attached and closed.

Just based on my own speculation, I'm wondering if the team needs a longer dark baseline. Maybe the optics are a bit noisier than anticipated.

Posted by: ustrax Mar 25 2009, 08:11 AM

Syrinx, according to Batalha, it took longer than expected to get really good calibration images. The had to do an extra telescope pointing just to be sure they got what they needed.

Posted by: PhilCo126 Mar 26 2009, 08:32 AM

Keep us posted on the dust cover jettison

Posted by: ustrax Mar 26 2009, 03:28 PM

FIRST LIGHT!...Slow down ustrax...
Kepler is opening its eyes, not the full ejection but some some sunlight made its way around the cover.
Ejection will probably take place early next week...
http://beyondthecradle.wordpress.com/2009/03/26/kepler-mission-first-light-update-with-jon-jenkins/

Posted by: HughFromAlice Mar 26 2009, 10:29 PM

What we might expect over the nominal mission - Quote from DK "talking about Earth-sized planets in a 1AU orbit, and we are expecting something like forty to fifty detections"

Posted by: AndyG Mar 27 2009, 09:02 AM

Hi Hugh,

I notice that he goes on to say it's based on the assumption that stars like our sun have terrestrial planets. Which means, I suppose, the number could be many hundreds (to include stars not like our sun) or, indeed, none (Earth The Cosmological Rarity).

As Tom Petty once sang ... the waiting is the hardest part. ;-)

Andy

Posted by: ustrax Mar 28 2009, 08:08 PM

Looks like you're not the only one thinking that thought...

"We’re having a hard time waiting for the dust cover to be released so that we can finally see what the stars look like through Kepler’s eyes. I’m confident that we won’t have to wait too much longer."

http://beyondthecradle.wordpress.com/2009/03/28/kepler-mission-first-light-update-for-280309-with-jon-jenkins/

Posted by: belleraphon1 Apr 1 2009, 02:39 PM

KEPLER went into limited safe mode on March 23..... on of the reasons the dust cover has not been released as yet.

"2009 March 30. Mission Manager Update - Engineers have determined the cause of Kepler's entry into limited safe mode last week, and are preparing to return the spacecraft to normal operations. In order for Kepler to know where it is in space, and to know where to point its high-gain antenna toward Earth, the spacecraft maintains information about its position, called a state vector, which updates ten times per second. Every few days, navigators on the ground update their knowledge of Kepler's actual orbit, and ground controllers upload a new state vector to the spacecraft. Engineers have concluded that, if the new state vector's start time is a multiple of 1,000 seconds from the start time of the previous vector, a momentary glitch occurs in the calculated spacecraft attitude. Even though this only lasts for one-tenth of a second, the spacecraft senses something it didn't expect and responds by pointing its solar arrays directly at the sun and awaiting further instructions from Earth. It will take a few days to ensure that everything is ready to proceed with commissioning, the next major step being release of the telescope's dust cover. March 30 14:00 UTC - Distance to Kepler: 2,362,000 km; 1,467,000 mi; 0.016 AU; 6.14 times the distance to the Moon."

http://kepler.nasa.gov/about/news.html

Craig

Posted by: imipak Apr 1 2009, 06:40 PM

Well, it's nice to know safe mode works properly, too

Posted by: ustrax Apr 1 2009, 09:15 PM

Kepler’s cover ejection will, most probably, take place ”mid next week“.

Posted by: belleraphon1 Apr 2 2009, 11:13 PM

Dust cover soon... space science takes patience...

2009 April 2. Mission Manager Update - Flight controllers have transitioned Kepler out of its low-activity safe mode and have powered on its main instrument, the photometer. The spacecraft is in what is called "standby
attitude" with the telescope pointed at the ecliptic North pole. Data will be collected from the photometer over the many hours it will take to stabilize the instrument at its operational temperature. The technical and programmatic reviews leading to dust-cover release are currently scheduled to be completed on Monday, April 6. Dust-cover release is scheduled to occur not earlier than Tuesday evening, April 7.

http://kepler.nasa.gov/about/news.html

Craig

Posted by: ustrax Apr 7 2009, 07:05 AM

Looks like, if everything goes well, http://beyondthecradle.wordpress.com/2009/04/07/kepler-mission-pre-prima-lux-update-with-jon-jenkins/...

"(Just like launch) assuming everything goes well from here on out, tomorrow (April 7) evening is going to be a big Kepler Mission milestone! So we’re getting pretty excited about seeing the stars for the first time, but will have to wait at least a few days since there are data transfer and processing delays."

Posted by: Syrinx Apr 8 2009, 04:39 AM

http://kepler.nasa.gov/about/news.html

2009 April 7 RELEASE: The dust cover on NASA's Kepler spacecraft is scheduled to be ejected tonight, no earlier than 6:30 p.m. Pacific Time, with a backup opportunity tomorrow evening.

Posted by: Greg Hullender Apr 8 2009, 05:07 AM

Ejected successfully!

http://www.spaceflightnow.com/news/n0904/07kepler/

--Greg

Posted by: lyford Apr 8 2009, 05:13 AM

http://www.nasa.gov/mission_pages/kepler/news/kepler-20090407.html!

Posted by: ustrax Apr 8 2009, 08:44 AM

Bring us those brave new worlds Kepler!

Posted by: MahFL Apr 8 2009, 05:31 PM

Anyone know how thick the "wire" was and was there back up circuits to power it and burn it through ?

Posted by: belleraphon1 Apr 8 2009, 11:50 PM

KEPLER is close to starting its science mission... I tremble with anticipation... eta sub E of the Drake equation is about to be quantified...

http://en.wikipedia.org/wiki/Drake_equation

We stand where Galileo did 400 years ago. What will we know in four years?

GLORIOUS!

Craig

Posted by: Vultur Apr 9 2009, 02:46 AM

According to http://www.planetary.org/blog/article/00001907/ about the dust cover ejection, Kepler is more than 3 million kilometers from Earth already. Wow...

(Hopefully that's far enough away from city lights... )

Posted by: ustrax Apr 16 2009, 05:01 PM

It's FULL of stars!!!
http://beyondthecradle.wordpress.com/2009/04/16/kepler-mission-its-full-of-stars/

Posted by: MahFL Apr 17 2009, 03:43 PM

And proberbly several earth like planets.

Posted by: Decepticon Apr 17 2009, 03:55 PM

A reconfirmation of TrES-2 would be nice first bit of news.

Posted by: remcook Apr 17 2009, 06:47 PM

Well, there's a transit every few days, so the Kepler scientists might have already seen it!

Posted by: Astro0 Apr 17 2009, 10:13 PM

Just for your amusement...
Seems as if Kepler has already made an astounding discovery according to this report.

http://www.denverpost.com/business/ci_12160163

So, it's already found them. The stars are 'Earth-like' (so not very bright then). To top that, according to the article... like Kepler, Ball Aerospace & Technologies is being controlled on a day-to-day basis by students at the University of Colorado.

A lovely job of taking probably what was a longer article or press release and then editing it so it makes no sense at all.

Posted by: Syrinx Apr 18 2009, 04:24 AM

FULL INLINE QUOTE REMOVED - ADMIN

Plenty of fail in that article. I have to wonder what the editors were busy with when that column hit their inbox for approval.

There may well be 100 Denver-based BLOGS with better and more accurate Kepler content. I love the internet.

Posted by: tacitus Apr 21 2009, 04:31 AM

So, any predictions as to when that will be?

At 2.5 days between transits, a solid confirmation will take between 5 and 7.5 days of observations, plus whatever wait time there is till the next scheduled download, and however long it takes to eke out the light curves from the data.

Before the middle of May, perchance?

Posted by: Syrinx Apr 21 2009, 06:41 PM

I would guess mid-May at the latest. Probably earlier. I think the team will probably use TrES for calibration.

During the science phase, the team will have monthly downlinks.

During the calibration phase, I'd expect the downlinks to be scheduled as needed.

Posted by: Decepticon Apr 22 2009, 08:05 AM

If TrES 2 Had any moons would that be detectable?

Posted by: Holder of the Two Leashes Apr 22 2009, 02:54 PM

Moons would appear in the transit data if they were as large as Titan or Ganymede, but given how close they would be to the planet, it is unlikely they would show up as separate signals. They would be averaged into their planet during the time intervals that Kepler could distinguish.

An excerpt from the mission manager updates on the main Kepler site ...

"2009 April 20. Mission Manager Update - The Kepler science team has decided that further refinement of the telescope's focus would significantly improve the mission's science return. The project is therefore proceeding with these adjustments. "

Posted by: Syrinx Apr 25 2009, 08:23 AM

http://www.nasa.gov/mission_pages/kepler/news/keplerm-20090424.html

Posted by: Holder of the Two Leashes Apr 26 2009, 09:44 PM

In an earlier reply I made to Deception's question about detecting moons around Tres-2, I gave myself some wiggle room by limiting the answer to "separate signals", without really answering the question (even though the answer "probably not" was implied). There would be some 30 minute intervals where a moon would show up alone, along with an equal number of cases where the planet would too, when the elongation was sufficient. My guess was there would not be enough of these intervals by themselves during the prime mission to add up to a detection. We're talking about a moon orbit here that is, at most, half the size of our own moon's orbit.

Provided, of course, that separate signals are really required. Whether there is a statistical methode for analysing the data in it's entirety, I didn't know, and still don't.

But now I found this little tidbit from http://pr.caltech.edu/periodicals/EandS/articles/LXIX3/odonovan.html:

"TrES-2 is the first transiting planet - or planet that passes directly between its star and Earth - to be found in an area of the sky known as the "Kepler field", ... Discovering TrES-2 beforehand allows Kepler's astronomers to plan additional observations of it, such as searching for moons."

Okay. My bad. My bad.

Posted by: Mongo Apr 26 2009, 09:54 PM

I would have thought that the main technique for discovering a large moon around Tres-2 would be timing variations. Since the planet's primary will be monitored continuously, we should end up with three years worth of transits and their timing. If the transit timing varies periodically with a period significantly smaller than Tres-2's orbital period (it should be possible to disentangle the putative moon's period from Tres-2's orbital period), I would think that the cause would have to be a moon.

As far as I know, no such variations have been found to date (on a limited number of transits), but with the huge number of transit observations expected during Kepler's primary mission, the margin of error for any timing variations should be considerably reduced from the current value.

Posted by: Holder of the Two Leashes Apr 26 2009, 10:29 PM

Again, I really don't know. But my understanding is that Kepler sums up a total of 30 minutes worth of observations ( the individual readouts being much, much shorter) and transmits this average value of half an hour as its reading for each pixel. Maybe I'm wrong about that. But if it is the case, it's a fairly coarse interval we're talking about.

The timing offset for the earth, caused by the moon, would be at most three minutes on either side of the average. Still, if you added up hundreds of transits... who knows?

Edit: from Wikipedia - "The CCDs are read out every three seconds and co-added on board for 15 minutes".

Posted by: Hungry4info Apr 27 2009, 12:21 AM

It's very unlikely TrES-2 b has any detectable moons, being so close to its parent star and thus having such a small hill radius.

Posted by: Mongo Apr 27 2009, 03:47 PM

I am sure that you are right, for that reason. Another Earth-Luna system might be detectable, provided that there were sufficient transits recorded. How close to its primary could an Earth-Luna twin be and remain stable, and would that result in sufficient monitored transits during the Kepler primary mission to tease out the satellite?

[searches ARXIV]

http://xxx.lanl.gov/abs/astro-ph/0306087

We investigate the improved detection of extrasolar planets around eclipsing binaries using eclipse minima timing, and extrasolar moons around transiting planets using transit timing, offered by the upcoming COROT (ESA, 2005), Kepler (NASA, 2007), and Eddington (ESA 2008) spacecraft missions. Hundreds of circum-binary planets should be discovered, and a thorough survey of moons around transiting planets will be accomplished by these missions.

http://xxx.lanl.gov/abs/0705.1046

Precise photometric measurements of the upcoming space missions allow the size, mass, and density of satellites of exoplanets to be determined. Here we present such an analysis using the photometric transit timing variation (TTV_p). We examined the light curve effects of both the transiting planet and its satellite. We define the photometric central time of the transit that is equivalent to the transit of a fixed photocenter. This point orbits the barycenter, and leads to the photometric transit timing variations. The exact value of TTV_p depends on the ratio of the density, the mass, and the size of the satellite and the planet. Since two of those parameters are independent, a reliable estimation of the density ratio leads to an estimation of the size and the mass of the exomoon. Upper estimations of the parameters are possible in the case when an upper limit of TTV_p is known. In case the density ratio cannot be estimated reliably, we propose an approximation with assuming equal densities. The presented photocenter TTV_p analysis predicts the size of the satellite better than the mass. We simulated transits of the Earth-Moon system in front of the Sun. The estimated size and mass of the Moon are 0.020 Earth-mass and 0.274 Earth-size if equal densities are assumed. This result is comparable to the real values within a factor of 2. If we include the real density ratio (about 0.6), the results are 0.010 Earth-Mass and 0.253 Earth-size, which agree with the real values within 20%.


So it looks like detection of sufficiently large exomoons via transit timing with both CoRoT and Kepler should be possible, if they exist.

Posted by: Holder of the Two Leashes Apr 27 2009, 05:02 PM

As I mentioned earlier, any moon of Tres-2 would have to be within about half a lunar distance of the planet to be stable. Say about 130,000 mile radius (forgive my english units here) for the orbit. My back of the envelop calculations, using Wiki values, showed a hill sphere of about a lunar distance. Over the long haul, only orbits about half the size of a hill sphere are truly stable, even if the orbit is retrograde.

Earth has a hill sphere of about four lunar distances, so the moon could effectively orbit to twice its distance (or four times for a geologically brief period). You could also keep the moon at its current distance, move the earth to half its current distance to the sun (not recommended), and still have a stable earth-moon system.

The most massive moon in our solar system is Ganymede. The mass ratio of Tres-2 : Ganymede is about 16,000 : 1.

If we put Ganymede in orbit around Tres-2 at 130,000 miles, the center of mass of the system is offset from the center of mass of the planet by 8 miles. At 50 miles/sec orbital speed of the planet about the star, the difference in transit timings at greatest elongation amount to about plus or minus 0.15 seconds from the expected. Over a fifteen minute integration of photometry, you get about a 0.02 per cent lightening or darkening over what you would expect during that interval.

The moon, by the way, would preceed or follow the planet by about 40 minutes at greatest elongation.

I welcome any efforts to check (and correct) my math here.

Posted by: Mongo Apr 27 2009, 05:57 PM

The math looks good to me.

Perhaps a more productive technique would be to look for any moons directly. The radius of TrES-2 is about 1.272 times that of Jupiter, or about 89,000 km. A large moon might be around 2,000 or 2,500 km in radius, for an areal ratio of 1270 to 1 (2,500 km) or 1980 to 1 (2,000 km). This would represent an additional dimming of up to about 0.08 percent of the drop due to the exoplanet occurring up to 40 minutes before or after second contact and a compensating rise occurring the same amount of time before or after third contact. Is 0.08% of the full lightcurve drop within the sensitivity of the Kepler detectors?

Actually, if both techniques were possible, both mass and radius (and hence density) of this hypothetical moon would be known, which would imply bulk composition -- very useful to know.

This would certainly be an easier task when dealing with hot Neptunes or superEarths, instead of TrES-2 in particular.

Posted by: Syrinx May 6 2009, 11:39 PM

http://www.nasa.gov/mission_pages/kepler/news/keplerm-20090501.html

Posted by: Syrinx May 8 2009, 06:31 AM

http://www.nasa.gov/mission_pages/kepler/news/keplerm-20090507.html

Posted by: Holder of the Two Leashes May 11 2009, 08:31 PM

According to the last mission manager report, they were suppose to decide today whether Kepler is ready to proceed with science observations. Haven't heard anything yet.

Depends on how close it is to the star. If Kepler could detect a moon this size with an eighty minute transit time of its own, and you are lucky enough to always catch it far away from the planet, then clearly yes. The 0.08% variance simply matches the size of the object that is detectable, so it would be within the sensitivity. But it won't always be 40 minutes of separation.

The two papers you listed seem to hint at a very optimistic outlook for Kepler finding moons. So I'm at a loss to explain it. These http://kepler.nasa.gov/sci/basis/sizes.html from the Kepler website would indicate to me that our own moon around the earth would not be detectable by Kepler, although earth itself would be.

It would help a lot if the Kepler website addressed the issue directly. Given the fact that a Jupiter size planet, in an earth like orbit, might possibly have earth sized moons, the omission of any talk of Kepler's ability to detect such moons seems a bit of an oversight.

Or maybe I missed something. Like on one of the education/outreach pages?

Posted by: Holder of the Two Leashes May 13 2009, 06:39 PM

The hunt is now underway! Best wishes for success.

http://www.nasa.gov/mission_pages/kepler/news/kepler-200905013.html

Posted by: tacitus May 13 2009, 08:45 PM

Indeed. I guess we're entering the "hurry up and wait" stage as we wait for the first announcements of hot Jupiters and the like.

I assume they won't be announcing anything for several months, even if they find some short period planets within the next few weeks?

Posted by: Drkskywxlt May 14 2009, 12:07 AM

The NASA press release says Jovians could be announced "as early as next year". I assume that allows them time to confirm the planets with radial velocity measurements. Hot Jupiters should pop out of their data immediately I would think...

Posted by: MahFL May 14 2009, 11:51 AM

I believe they said it would take a while before Earth like planets could be identified for certain, like 3 years. But I bet before three years they will say, "yes we have X number of dimming's that might be Earth like".
I expect many Earth like planets will be discovered.

Posted by: centsworth_II May 14 2009, 01:52 PM

It will be really interesting to see what ratio of Earth-like to Jupiter-like planets emerges over the years. To see how typical our solar system is in that respect.

Posted by: ustrax May 27 2009, 06:24 AM

Drink southwesterner hollow fog grog

Posted by: tacitus May 29 2009, 11:49 PM

From the latest http://kepler.nasa.gov/about/news.html:

You know, it's just not fair to tease us like this!

Posted by: Greg Hullender May 30 2009, 05:00 AM

They did say that the first science data would be downloaded on June 18. I'm not expecting anything at all before then -- and not expecting much for a while afterwards, I'm afraid. They've been pretty clear that they don't intend to be generous with their data.

--Greg

Posted by: nprev May 30 2009, 07:01 AM

I'd bet that it's more an abundance of caution then a lack of generosity. Expectation management's gonna be pretty important; you know there will be worldwide banner headlines trumpeting "New Earth(s)". It will be tough enough for the Kepler team to explain to the general public that the planets are really far away so there will be no pretty pictures & definitely no physical voyages to them.

Posted by: tacitus May 30 2009, 11:35 AM

Yeah, I was just kidding with the tease comment. Even if they see Earth-like planet transits in the first data download, they're not going to announce anything until they've seen it happen two more times, which might not be for another two years. It is nice to know that the telescope is working extremely well, by the sound of it.

(And I am fine with vague updates on the quality of the data -- beats not hearing anything for a year or more!)

Mind you, there should be ample time before June 18th to see three transits from a hot-Jupiter, so we should be hearing something fairly soon after that. I guess the question is will they announce confirmed results before any papers are written?

Posted by: Greg Hullender May 30 2009, 04:09 PM

More charitably, there's some chance they'll spend months tweaking their classification software. I built a speech recognizer this week (part of a seminar at UW) and found lots of surprises in how the data interacted with my models. Speech reco is a very well studied field, whereas the Kepler guys are out in new territory -- studying much smaller changes in brightness than anyone has before. It wouldn't surprise me if they spend months arguing about what the data actually mean. I can't blame them for not wanting to have that argument in public.

Even though it would be really, really cool to be part of that argument. :-)

--Greg

Posted by: ustrax Jun 1 2009, 10:08 AM

Dandy sargent hunts with sonnet.

Posted by: imipak Jun 1 2009, 08:17 PM

Yes, let's hope "they" will bring the distant stars closer to our eyes...

(EDIT: don't get me wrong - I've no idea what they mean, just a dim idea about what they are... )

Posted by: ngunn Jun 1 2009, 09:26 PM

What are they? Crossword clues? Sub-intelligible advertising? Paranoia food (obvious to everyone except me)? Randomness lures (even nonsense may have a purpose)?

I tried anagrams, but shunt tonnes with Dynad garnets doesn't seem like an improvement.

Posted by: Pavel Jun 2 2009, 08:49 PM

I guess it's anagrams for ideas that could be either true or crazy. If the idea confirmed, ustrax will show us that he knew it already. For examples of anagram use in astronomy, see
http://www.hps.cam.ac.uk/starry/galtele.html

Posted by: ustrax Jun 3 2009, 10:53 AM

Anagrams they are.

Half hip mahatmas broken limitedness.

Posted by: hendric Jun 3 2009, 05:35 PM

Ha, I thought they were difficult phrases for Greg's speech analyzer.

Posted by: belleraphon1 Jun 3 2009, 11:11 PM

Spitzer warm mission will contribute to verifying and analyzing Kepler planet candidates...

From AAS abstracts session 210: http://aas.org/meetings/aas214/schedule_scientific.php

Confirmation and Characterization of Kepler Mission Exoplanets: The Era of Rock and Ice Exoplanets
Topic: None selected
Heather Knutson1, D. Charbonneau1
1Harvard-Smithsonian Center for Astrophysics.
Presentation Number: 210.03
Facility Keyword: Spitzer
In the past 4 years, the combination of ground-based transit surveys and the remarkable stability of the Spitzer Space Telescope permitted the direct investigation of the atmospheres of one specific class of exoplanet, namely the Hot Jupiters. The NASA Kepler mission (scheduled for launch early this year) will have the ability to discover dozens of transiting exoplanets that are not currently detectable from the ground, including large numbers of transiting hot Neptune and hot Super-Earth exoplanets, as well as cooler Jupiters. Our Exploration Science program will measure the two-color planetary emission for 20 representative members of these previously inaccessible exoplanets, providing the first opportunity to directly test theoretical models of exoplanetary atmospheres of varying compositions (notably Super-Earths and Neptunes) and under differing levels of irradiation (cooler Jovian companions). The same data will permit an estimate of the orbital eccentricities, thus providing a test of models of the orbital migration and tidal dissipation for these various types of exoplanets. We will also use Spitzer to follow up Kepler-identified candidate terrestrial exoplanets to prove that these signals are indeed planetary in origin. By gathering single color time series spanning times of primary transit, we will exclude a significant source of astrophysical false positives (resulting from blends of triple star systems containing an eclipsing binary) that can precisely mimic an exoplanetary signature in the Kepler data. These infrared data will provide a crucial confirmation of the planetary nature of the most exciting terrestrial-planet candidates.

Craig

Posted by: Holder of the Two Leashes Jun 4 2009, 04:14 PM

Here are a couple of web pages on the topic of exomoon detection:

http://www.centauri-dreams.org/?p=3856

http://xxx.lanl.gov/abs/0810.2243

Also, there is an interesting full length article on the topic in the July issue of Sky and Telescope, which is out now.

I'm sure you're right. The very first download, due in just a few days, stands a good chance of having a small planet detection somewhere in the data. A long time before they sort out false detections, eclipsing binary backgrounds, and establish orbital periods, they should have a real good statistical idea of just how many earth class detections they are going to end up with.

Posted by: ustrax Jun 9 2009, 06:48 AM

Infighters often reign.

Posted by: ugordan Jun 9 2009, 08:05 AM

Yeah, I'm not getting any of that.

You tease.

Posted by: remcook Jun 9 2009, 11:04 AM

I hate anagrams. I'll just wait till the official announcement.

Posted by: ngunn Jun 9 2009, 11:08 AM

Enter, offering insight (please!).

Posted by: Holder of the Two Leashes Jun 9 2009, 10:12 PM

Is the source material for the anagrams in English, or are you scambling sentences in Portuguese (or some other language) into English words?

Posted by: Stu Jun 9 2009, 10:16 PM

Ok, now you're scaring me; you really sounded like Yoda there...

Posted by: Greg Hullender Jun 10 2009, 05:54 PM

Is anyone else ready for an anagram moratorium? Or at least a separate anagram thread? I get excited to see a new post under Kepler, then annoyed that it's just another anagram.

--Greg

Posted by: djellison Jun 10 2009, 06:32 PM

I'm with you Greg.

Posted by: Hungry4info Jun 10 2009, 07:19 PM

Same here. I've begun to realise that if you don't have anything to report, don't tease us.
Got angered at CoRoT for teasing everyone with "hints of a 1.7 Earth-radius transiting planet" for a couple years before CoRoT-7b was announced.
Anagrams, cryptic information, (and sometimes, as with CoRoT-2 b, press releases) just serve to raise public hopes beyond that which can be satisfied by what the piece of news actually is. This will backfire some, causing some animosity toward the mission.

Anyone remember that? CoRoT-2 b's announcement?
"Oh you guys are going to love this, wait for it... wait for it... wait for it.... history will be made...
OH MY GOSH!!! We found a HOT JUPIER!! OMG! Can you believe that?"

NASA's announcement of the SWEEPS planets back in October of 2006 was almost as bad.

My point is that if you sit on data, make sure it's all good, and then release it out of nowhere, everyone's surprised, and pleasantly excited, and we all love the mission that much more. It's a lot better than a CoRoT-2 style let-down.

Edit: Besides, if the data is scheduled for a Jun 18 download, what on Earth (har har) is there to make an anagram about anyway?

Posted by: stevesliva Jun 10 2009, 07:50 PM

Are there worries about not being credited with discovery in these games? Does the Haumea tempest have people pre-releasing these discoveries in encrypted form?

Posted by: Holder of the Two Leashes Jun 10 2009, 08:06 PM

Ten days worth of calibration data, which could easily have picked up an exoearth or two if they are as common as has been assumed.

For those looking for substance, there is a new (well, two days old) http://kepler.nasa.gov/about/manager.html out.

Edit: I'd better mention that it would be impossible to confirm said planets if they were in anything remotely resembling a habitable zone. Merely that their transits would be present.

Also, I believe that if it's something you're not suppose to come right out and say, whatever it is, then best not to mention it at all.

Posted by: Syrinx Jun 10 2009, 08:53 PM

eys.

Posted by: remcook Jun 11 2009, 07:25 AM

Unless it's a starspot of course. It's hard to tell anything from just one transit. You need the follow-up observations. And if you have multiple transits in just 10 days then I think it's save to say it's not in the 'habitable zone'.

Posted by: belleraphon1 Jun 11 2009, 01:33 PM

No anagrams please! I am neither pleased nor amused by them.

This is not a game.... we are talking about getting real answers to questions this species has had since we first had minds to appreciate the sky.

Craig

Posted by: Holder of the Two Leashes Jun 11 2009, 02:09 PM

My edit in the post you are quoting (and which you left out) was made within the hour of my first posting it, and addressed both those issues.

Any true detection at this point is only going to be regarded as a candidate detection, but as was previously pointed out, all the true and false detections together, at some point early on, will add up to a number higher than just the statistically anticipated false detections. Without being able to say exactly which detections are real, the Kepler team will be able to say about how many planets they have in the data. Whether they share this information any time soon, or only want to release confirmed planets at a later date, remains to be seen.

Posted by: Syrinx Jun 16 2009, 10:18 PM

We're less than two days away from the first science data downlink! I don't think anyone expects the data to be released for quite some time. But hopefully we'll have confirmation that it was at least received.

Posted by: Holder of the Two Leashes Jun 21 2009, 08:22 PM

First, everything is OK, and the first precious load of science data is safely on the ground.

Back on June 15th, there was a hiccup when Kepler went into safe mode for a day and a half. Some science time was lost, but they anticipated having this happen a few times during the mission.

Download occurred on scheduel, and the quarterly spacecraft roll was executed successfully.

I expect that somewhere in download number one, there are a few small golden nuggets to pan for. But it'll take some more buckets of data to sort out the "fools gold" from the real.

http://kepler.nasa.gov/about/manager.html

Posted by: Syrinx Jul 7 2009, 11:07 PM

http://www.nasa.gov/mission_pages/kepler/news/keplerm-20090707.html

Posted by: Gladstoner Jul 8 2009, 08:12 PM

.

Posted by: siravan Jul 24 2009, 12:29 AM

latest update

http://www.nasa.gov/mission_pages/kepler/news/keplerm-20090723.html

Posted by: Greg Hullender Jul 24 2009, 04:18 AM

Sadly, this latest "update" tells us nothing except that there hasn't been another safe-mode event. I realize they have their reasons (as I've said before) but it's a pity they can toss us a bone or two.

--Greg

Posted by: Gsnorgathon Jul 24 2009, 05:56 AM

Patience, Grasshopper. (And no more safing events sounds mighty good to me!)

Posted by: Greg Hullender Jul 24 2009, 11:27 PM

Thank you, wise and quiet neighbor. :-) Perhaps I should invite you and Van over for a beer sometime.

--Greg

Posted by: Gsnorgathon Jul 27 2009, 04:43 PM

Hey - I totally understand the impatience. I think Kepler is my fave mission right now (and isn't it cool that we have so many to choose from?!), but it's definitely not an instant-gratification mission. Cassini, Messenger, half-a-dozen (well, close enough) Mars missions... lots of pretty pictures to just go ooh! and aah! over as soon as they're downlinked. Kepler... not so much. But when the missions scientists get done massaging the data into something they can release - man-oh-man! In a way, Kepler's a thousand (or more!) planetary missions in one. Just thinking about it gets the salivary glands going. Now where's my drool bucket?

Posted by: belleraphon1 Jul 28 2009, 05:03 PM

Yes, patience is a necessary commodity here. I do not want hints, or anagrams (with due apologies to the great Galileo, living, as he did, in a time when the truth could get you killed).

I want the data and the truth that delivers.

Will be interesting in a year to compare Kepler results to Corot. Are the lack of planet detections by Corot a factor of instrumental effects or obervational hindrance, or real? Kepler will weigh in on that.

RV studies predict approximately 30% solar type stars have terrestrial mass planets in inner regions.
Why does Corot refute that?

The truth is what matters The universe does not care what we want.

Fascinating times ahead.

Craig

Posted by: Decepticon Jul 28 2009, 10:19 PM

It also gives us what we don't expect!

Posted by: belleraphon1 Jul 31 2009, 08:38 PM

See KEPLER forum where I stand partly corrected... looks like instrumental effects limited COROT's yield.

page 6 of..
http://fr.arxiv.org/PS_cache/arxiv/pdf/0907/0907.5150v1.pdf

Craig

Posted by: belleraphon1 Aug 1 2009, 02:10 AM

Should have said COROT above, not KEPLER.

Craig

Posted by: stewjack Aug 1 2009, 12:24 PM

http://www.nasa.gov/multimedia/nasatv/MM_NTV_Breaking.html

August 6, Thursday
2 p.m. - Kepler Mission News Conference - HQ (Public and Media Channels)

That's 18:00 GMT/UTC for those who don't live on the U.S. east coast.

Posted by: Mongo Aug 1 2009, 01:29 PM

Hey, that's my birthday!

Looking forward to a nice prezzy from NASA...

Bill

Posted by: belleraphon1 Aug 1 2009, 06:05 PM

Look forward to this, but... Like to see the list of presenters....

Remember, what the general public considers newsworthy is not the same as what most of us here on UMSF would consider newsworthy.

I would not expect any firm planetary announcements... way too soon for that. But do expect a report on
sensitivity and maybe a qualitative hint about first look candidates. Any actual transits will need RV confirmations which take time.

Then again... I hope they blow my news conference prediction away. Maybe Mongo and all of us will get a neat present.

Craig

Posted by: siravan Aug 2 2009, 02:39 AM

I'm not sure about RV confirmation. Kepler is different from Corot. It is possible to confirm planetary candidates detected by Corot using RV, but Kepler is much more sensitive and most of its detections will fall below detection level of currently available spectrographs (HARPS and SOPHIE). Of course, RV method is still useful in rejection background binaries. I suspect most of the "planets" found by Kepler will remain in candidate status for a while.

Posted by: Syrinx Aug 2 2009, 07:10 AM

Well this press conference is certainly unexpected.

I can't imagine that it will contain anything other than information and good news. Two safe mode events don't warrant a press conference, which is the only bad news so far however slight.

Maybe a confirmation of the previously-known extrasolar planets in Kepler's view? TrES-2b, HAT-P-7b, and HAT-P-11b all have orbital periods under 5 days, thus Kepler should have spied plenty of transits for them by now.

Posted by: Byran Aug 2 2009, 01:28 PM

http://nexsci.caltech.edu/missions/KeckSolicitation/proposal-current.shtml

http://www2.keck.hawaii.edu/observing/schedule/index.php
Borucki users HIRES 29-31.07.2009, 01-09.09.2009, 3-5.10.2009, 28-29.10.2009

Discovery hot jupiter users about 10 RV-measurements or 20 minut time Keck-HIRES.

My forecast conferences NASA on August 6 - present 10-100 new hot transit gas giants planets depending on numbers false planet candidate

Posted by: Hungry4info Aug 2 2009, 01:52 PM

I made a similar guess-timate about the first CoRoT press conference. The announcement of a single hot Juptier was more-or-less a disappointment.

I learned my lesson.

Posted by: Greg Hullender Aug 2 2009, 02:50 PM

Yeah, it makes sense that they'd be announcing their first planet discoveries. I guess the real questions would be a) how many and down to what sizes? Given they've got several weeks of data, they might be able to report Mercury-sized objects in 7-day orbits -- if any such exists.

Posted by: Syrinx Aug 2 2009, 11:55 PM

Only one set of those dates (July 29, 30, 31) is in the past.


What sort of time allocation does one reserve at Keck? Just from their web page it seems two teams split one night. So would that mean Borucki/Marcy had ~6 hours x 3 days = ~18 hours?

Anyway, I'm guessing Borucki/Marcy had to schedule their Keck time long ago before they even knew how many candidates they'd have. So I think correlating reserved Keck time with candidate quantity is specious.

Then of course there may be other additional teams confirming Kepler's results with other telescopes.

Hard for me to guess. I wasn't expecting any announcements any time soon, so anything more than a brief update is butter to me.

Posted by: Byran Aug 3 2009, 07:03 AM

I do not know. High probability that 50% on 50%.

Posted by: Hungry4info Aug 3 2009, 11:17 AM

If I had to guess, I would say the press conference is both about spacecraft problems, and TrES-2 b.

Posted by: stevesliva Aug 3 2009, 02:56 PM

Pessimist. Couldn't help but start thinking, "A spoonful of sugar helps the medicine go down..."

Posted by: ustrax Aug 3 2009, 02:56 PM

I would put my money here...well...maybe not all of it...

Posted by: Sunspot Aug 3 2009, 03:45 PM

Well I did just receive this in another email

"WASHINGTON -- NASA will hold a media briefing on Thursday, Aug. 6, at
2 p.m. EDT, to discuss early science results of the Kepler mission. "

It doesn't make any reference to spacecraft problems...

Posted by: Byran Aug 3 2009, 05:49 PM

http://news.yahoo.com/s/usnw/20090803/pl_usnw/nasa_announces_briefing_about_kepler_s_early_science_results

after three consecutive nights of observations with Mauna Kea (W. M. Keck Observatory ) in Washington at a press conference with hot dog (planets)

Posted by: belleraphon1 Aug 4 2009, 02:19 AM

From spaceref.com

Editor's's note: According to multiple sources, Kepler has not found anything "new". However it has successfully detected at least one previously discovered substellar object circling another star. In other words, this amazing little spacecraft works!

http://www.spaceref.com/news/viewpr.html?pid=28885

Craig

Posted by: Hungry4info Aug 4 2009, 01:22 PM

My pessimism never fails! Haha.

I still look forward to the press release.

Posted by: ustrax Aug 4 2009, 04:33 PM

That is not entirely true.

Posted by: Stu Aug 4 2009, 05:33 PM

Ok, Mr Inside Knowledge, which part of that previous post isn't "entirely true"?

Posted by: PhilCo126 Aug 4 2009, 05:51 PM

Looking forward to Thursday's press conference... even with Kepler telescope's larger field of view and better optics, 3 transits are needed to confirm an exo-planet. So why shouldn't they require RV (Radial Velocity) confirmations... It could speed up the science output?

Posted by: ustrax Aug 4 2009, 06:08 PM

Is it Friday already?...
I know nothing...but we'll have new articles at BtC on the 6th.
I have the feeling that Hungry4info can keep a little bit of the pessimism after the conference...

Posted by: NGC3314 Aug 4 2009, 07:10 PM

AFAIK, radial-velocity data cannot now reach the precision to see the Doppler signature of the Earth on the Sun, which is the spot everyone hopes Kepler reaches. For most potential host stars, noise due to such things as convective features on the star limits the precision reachable no matter how good the photon statistics are. However, radial-velocity confirmation of a different kind can come from changes in the star's velocity centroid during transit (the Rossiter-McLaughlin effect), which can have a rather larger amplitude than the reflex Doppler shift. Happening only during a single transit, it also places less stringent requirements on the star's own long-term stability in centroid velocity. Anyway, that's how I'd approach the followup. (Well, that and attempts to winnow out projected third stars blended with ordinary eclipsing binaries; RV studies could do a fair job at that by seeing multiple velocity components all the time).

Posted by: Gsnorgathon Aug 4 2009, 07:32 PM

For those who didn't click through, let's take a look at the rest of that editor's note: "In addition, new candidate exoplanets have also been discovered but await confirmation by other telescopes. The results of Kepler's observations will appear in an article in this week's edition of Science magazine."

Posted by: Syrinx Aug 4 2009, 10:29 PM

Hah. That extra part wasn't there earlier today. It's been edited.

Posted by: belleraphon1 Aug 4 2009, 10:30 PM

Gsnorgathon

that additional note was added AFTER my posting. SO.. everyone... "keep watching the skies...."

Seriously... not sure what sort of article will appear in Science, but that is a one heck of a fast track for publication.
So not sure if this will be a peer reviewed paper, or an editorial article from Kepler participants.

Let's all stay tuned...

BOY I love this... a real encyclopedia of worlds we will have in 20 years.

Craig

Posted by: Holder of the Two Leashes Aug 5 2009, 01:18 AM

Exceeds.

Posted by: Gsnorgathon Aug 5 2009, 01:39 AM

Ah... interesting that that bit was added later, isn't it? And yeah, the prospect of this press conference has me reaching for my drool bucket, for sure. (And the cold, hard realist is saying "hold on son - the real juicy bits won't come until later.")

Posted by: Hungry4info Aug 5 2009, 04:05 PM

Even though we can't detect an Earth in an Earth-like orbit, we can set limits on its mass. The transit periodicity tells us the semi-major axis, radius, and orbital period, based on the mass and size of the star. We'll know if the planet is in the habitable zone.

If we don't detect the planet, this may be better news than if we do, as the planet would thus be fairly low-mass. If we do detect the planet, then it certainly won't be Earth-like.

On the other-hand, being that we know that RV signal to look for, we might be able to detect an Earth-like planet in the habitable zone. The inability to detect Earth analogues around solar-type stars is partly because we don't know where to look in the data. It's just a sea of dots on a graph. Transit detection will tell us what period to look around, and the transit ephemeris will tell us where the signal will be.

Searching for planets with Kepler transit photometry already in hand will be like saying "Here is the planet, we already know where it's RV curve is, and we already know it is there." This will allow much lower planet-masses to be discovered than blind-searching.

Posted by: ustrax Aug 6 2009, 08:40 AM

EDITED: If only Galileo was here...

EDITED
Sorry Ustrax - we've said no more rhyme and riddle - ADMIN

Posted by: Stu Aug 6 2009, 04:06 PM

At the rate they're downplaying things now, I'm fully expecting the head of the Kepler team to stand up at today's press conference and say "Sorry to disappoint you all, but we haven't found any Earth sized planets yet. But hey, some good news, I found my car keys!" ...

Posted by: ustrax Aug 6 2009, 05:42 PM

Stu...I guess we all know it isn't about that...
Now about those car keys...where were they occulted?...under his hat?
Articles by Jon Jenkins and Natalie Batalha at BtC when the clock marks 2.02PM EDT.

EDITED: Here they are:

http://beyondthecradle.wordpress.com/2009/08/05/hat-p-7b-confirmation-and-many-great-things-to-come-with-natalie-batalha/

http://beyondthecradle.wordpress.com/2009/08/06/622/

Posted by: PhilCo126 Aug 6 2009, 06:23 PM

Dr Alan Boss showed an interesting graph of the already 352 exo-planet detected with graph-axes; Earth masses versus Orbital distance...
Is this graph available online?

Posted by: ustrax Aug 6 2009, 06:26 PM

Here Phil: http://kepler.nasa.gov/media/earlyresults/AlanBoss-PlanetDistro.jpg
All of the images are at the mission's website:
http://kepler.nasa.gov/press/earlyresults.html

Posted by: Greg Hullender Aug 6 2009, 06:48 PM

Interesting that HAT-P-7 is so much hotter on one side but that the other two are not. I wish they'd posted the data for all three, just so we could compare and contrast. Perhaps that'll all be in tomorrow's article in Science.

--Greg

Posted by: PhilCo126 Aug 6 2009, 06:48 PM

Press meeting summary:
1. Kepler Space Telescope's detector works fine and it's capable of detecting Earth-sized exo-planets.
2. Optical wavelength detection of the phase curve of the planet HAT P-7b... accuracy is everything

Posted by: Hungry4info Aug 6 2009, 06:50 PM

I found myself mildly excited by this press conference. Exciting to know that they've already achieved this precision.
Thanks for all the links.

Posted by: belleraphon1 Aug 6 2009, 07:06 PM

From Natalie Batalha's comments in BtC.. thanks Ustrax..

"Many of the light curves looked like they were drawn with a fine-point marker. I sent a sample light curve to a colleague and he replied asking me to please send the raw data as opposed to the “smoothed” data that hides the noise. It was a pleasure to tell him that this WAS the raw data."

That is exactly what struck me during the press conference... how clean that light curve looks... a beautiful line..

Much to look forward to...

Craig

Posted by: AndyG Aug 6 2009, 07:24 PM

... I think sums that up. Excellent news.

Andy

Posted by: Syrinx Aug 6 2009, 08:42 PM

I took a couple screen caps during the press conference.





Was anyone else highly disappointed by the Q&A? All their questions were either useless or answerable by Wikipedia. I was hoping Planetary Society might dial in with some intelligent questions.

- Put this into perspective for an average joe.
- How far away is HAT-P-7b?
- How hot is HAT-P-7b?
- How far away is Kepler?

Nobody asked how many Earth candidates they may have found!? And even the principal investigator hinted at something about it! He said about Earth-size planets: "We need three data points, and for all we know we may already have one of them."

Posted by: ustrax Aug 6 2009, 09:37 PM

You were? Than I must assume that you don't know what Kepler is about and that you don't value the science taking place.
Since the beggining the team points to 2012 as the timeline for results regarding an Earth-like planet.
Are you disappointed by the fact they have decided to come up front and tell us what is going on until then?
I am disappointed with you for not rejoicing with the fact that Kepler ACTUALLY works. That is what I've got from this conference, the thing is really able to detect an Earth-size planet. And...who knows? It might have found one already...Guess one have to be patient and not disappointed.

Posted by: centsworth_II Aug 6 2009, 09:42 PM

Ustrax, I think you are confusing disappointment with the questions following the briefing for disappointment with the briefing itself. One can be excited about the briefing and then disappointed in the questions following it. In fact, the more exciting the news, the more disappointing the lack of good questions will be.

(I didn't see the briefing myself.)

Posted by: Syrinx Aug 6 2009, 09:50 PM

As was noted in the reply above, you're confused by my definition of Q&A.

I was disappointed by the questions asked during the Q&A session at the end of the press conference. It seemed like the people asking the questions didn't bother to learn anything about Kepler before the briefing.

"How far away is Kepler?" You have got to be kidding me.

Posted by: ustrax Aug 6 2009, 10:01 PM

Sorry for the misunderstanding Syrinx...and thank you centsworth_II...I was taking it too serious...I have to deal with this another way...hey! I can always anagram it!

Posted by: tacitus Aug 7 2009, 05:32 AM

Gah! I missed the press conference because I was in the middle of negotiating a fair valuation for my house regarding property taxes!

Anyway, most of it is now on YouTube, if you missed it too -- here's the link to part 1, with two more parts posted by the same user.


http://www.youtube.com/watch?v=iWvpQ5Jwyfg

The space-multimedia archive site will probably have the full video at some point in the next day or two.

Anyway, this is fantastic news! I guess after Hubble's trials, there's always that period of worry and second guessing before you get the first block of science data and the instrument finally checks out okay.

Posted by: Paolo Aug 7 2009, 07:00 AM

Kepler's HAT-P-7 lightcurve is the subject of a paper in Science this week http://www.sciencemag.org/cgi/content/abstract/325/5941/709

Posted by: Reed Aug 7 2009, 07:15 AM

The whole thing is on the official NASA TV youtube channel http://www.youtube.com/watch?v=qRN7fNkZ-IQ

Posted by: Zvezdichko Aug 7 2009, 02:44 PM

I'm extremely excited. But there's no way to detect the composition of the atmosphere, right?

Posted by: Hungry4info Aug 7 2009, 03:32 PM

Depends on the planet. If the star is sufficiently bright then you might get a high enough SNR to say something about the atmosphere (i.e. like HD 209458 b and HD 189733 b, but these planets are exceptional cases). It won't be done with Kepler though, all it has is a photometer.

Posted by: Greg Hullender Aug 7 2009, 03:36 PM

That came up in the press conference, and the answer is that Kepler can't do that, but some of the future missions being proposed would be able to.

By the way, in case anyone missed it, this is what a Jovian planet looks like when you have four transits to work with. Had this been Earth and the Sun, the transit (the big drop) would have been about 2/3 the depth of the occultation (the little drop). So, yes, Earth-like planets should be detectable, but it's going to be close.

Something else interesting from the conference and some of the links was that the light curves of the variable stars are often unlike anything in the literature. Apparently the atmospheric noise has been hiding significant behavior. This complicates finding planets, of course, since their models for spotting variable stars have to be reworked.

--Greg

Posted by: stevesliva Aug 7 2009, 03:45 PM

ustrax's couple writeups were extremely interesting.

I thought it was cool that the warm Spitzer was mentioned as an observatory likely to follow up on new discoveries. I love it when old missions come in handy.

Posted by: Marz Aug 7 2009, 04:49 PM

I have some questions, if anyone can answer them.

1. Kepler's mission is only 3.5 years, barely enough time to confirm it's own initial discoveries. It sounds likely that the mission can be extended, so what is the expected longevity of the mission (assuming funding is not the problem)?

2. From the mission website: "Expected Results:

From transits of terrestrial planets in one year orbits:

About 50 planets if most are the same size as Earth (R~1.0 Re) and none larger,
About 185 planets if most have a size of R~1.3 Re,
About 640 planets if most have a size of R~2.2 Re,
About 12% with two or more planets per system. "

-- would these expected numbers scale linearly with mission extensions (i.e. would another 4 years of observing double these numbers)? Or is Kepler's field of view fixed to one region, so the sample set is difficult to change, and if this is the case, would most new planets found be longer orbital periods?

3. "Stellar evolution models are used to estimate the mass, radius and metalicity of the parent star"
-- how reliable are these models? Is there any way to directly determine these values, or does it require an instrument like the Terrestrial Planet Finder?

4. For gas giants found within a habital zone of the star, would it be possible to search for large moons with either Kepler or astrometry of the gas giant using ground-based instruments?

Posted by: Syrinx Aug 7 2009, 06:45 PM

Four years or so I think. Fuel is the problem. Kepler's gyroscopes must be de-saturated every so often. Eventually the fuel will run out, the gyroscopes will become saturated, and the entire spacecraft will lose its ability to point.

Yes, it's fixed. As such, the useful data return will decline with age.

I would imagine very reliable.

We had that discussion earlier in the thread I think. If I remember, yes it's possible but very difficult.

Posted by: Syrinx Aug 7 2009, 07:04 PM

That is not a free article. Anyone with access care to summarize (not plagiarize) the new and interesting parts, if any?

Posted by: Paolo Aug 7 2009, 07:24 PM

It's mostly the same things reported in the press conference yesterday. There is a good summary in Sky & Telescope's website
http://www.skyandtelescope.com/community/skyblog/newsblog/52657352.html

Posted by: hendric Aug 7 2009, 08:21 PM

Kepler is using a defocused star image, right? Is it a defocused mirror? What if instead of a defocused mirror, they put in a lens with severe chromatic abberation. They'll still get defocused images, since the colors would be spread around the whole star, but a circular integral around the star could yield some useful information. Dumb idea, or should I call a patent lawyer?

Posted by: siravan Aug 7 2009, 09:29 PM

IIRC, Kepler has a spherical mirror, which I think is much easier to make than parabolic mirrors needed to fix the spherical aberration. I guess there is not much point is going through the extra work of making it parabolic, just to defocus it with a secondary lens.

Posted by: siravan Aug 7 2009, 09:44 PM

Metalicity is measured directly spectroscopically. Mass can be measured directly if the star is binary (or tertiaty...). Of course, for exoplanets the main focus of interest is on single stars (as least partly due to the old discussion about possibility of habitable planets orbiting binary stars) and this is one of the reasons to use stellar evolution models.

Posted by: scalbers Aug 8 2009, 08:41 PM

There was some discussion of exoplanet moons with help from the transit timing method in this post (#158):

http://www.unmannedspaceflight.com/index.php?showtopic=1459&st=150&p=139639&#entry139639

And I think I read of the possibility of "amateur" transit timings even contributing to the search. Was this in Sky and Telescope or somewhere? There are some websites mentioning this as well.

Posted by: NGC3314 Aug 8 2009, 10:15 PM

We can get masses for members of binary stars. The standard relations between mass and luminosity come from members of widely separated binaries, where the stars are too small compared to the orbits to have affected one another's evolution (yet). http://physics.uoregon.edu/~jimbrau/BrauImNew/Chap17/FG17_24.jpg is a typical set of mass-luminosity and mass-radius relations for main-sequence stars. Eyeballing that scatter, it looks like 20% in luminosity if mass is known or 10% in mass if luminosity is known (since it's a steep function). Radius looks a bit worse; that often has to come from blackbody laws and the effective temperature and luminosity; which come from spectroscopy and from photometry plus parallax. That can be improved for stars not too distant; I saw a result from the CHARA interferometer in which they resolved the disk of one of the stars with a transiting planet, reducing its uncertainty in radius. (They are a long way from getting an interferometric signal from the dark planetary disk, alas).

As has been posted already, we get metallicity from spectroscopy, calibrated to the Sun. (Kind of odd that the best-fitting spectroscopic oxygen abundance there is not the best-fitting one for helioseismology. A lot of other things may shift a bit when that gets sorted out).

Posted by: middleschoolsteve Aug 9 2009, 04:50 PM

I'm quite curious to learn more about the light curves of some of the other variable stars, not necessarily curves which look like they may be planet transits. It sounds like they may have unique and exciting data. I wonder where and when these other data will be reported.
Wouldn't it be something if it turns out that Kepler's Earth sized planets are a minor part of what its data yields?
steve

Posted by: Hungry4info Aug 9 2009, 10:26 PM

I have no doubt that that the majority of stars with photometric variability will be intrinsically variable.
But I would sure like to be wrong!

Posted by: tacitus Aug 11 2009, 09:52 PM

The dataset all comes down together, so the timing of the non-exoplanet science results depends entirely upon the priority the science team gives it, and how many people they have working on it. It's probably not the highest priority, but if something highly unexpected falls out of the data, I suspect they will need to characterize fairly quickly it so they can rule out the possibility that it's caused by some type of exoplanet.

A non-exoplanet discovery would have to be really something to trump the discovery of habitable-zone Earth-twin planets. Unless it was something to do with solving current cosmological head-scratchers, like dark matter or dark energy, then I don't really know what would qualify as a show-stopper.

Discovering a Dyson's Sphere, perhaps....

Posted by: Stu Aug 11 2009, 10:10 PM

Either that or a full sized Culture habitat, or a huge Romulan mining ship firing "Red Matter" bombs..?

Posted by: siravan Aug 11 2009, 10:12 PM

How do you discover a Dyson's sphere using photometry method? I thought you need infrared imaging for that

Posted by: john_s Aug 11 2009, 10:19 PM

Periodic flashes of starlight through the windows...

Posted by: Stu Aug 11 2009, 10:21 PM

...or through holes punched in the outer shell by meteoroid impacts..?

Posted by: Hungry4info Aug 11 2009, 11:21 PM

They'd have to be some fairly large holes to be detected by Kepler.
But if you build a Dyson sphere, and you still have asteroids in your solar system, you're just begging for it to get hit

Posted by: tacitus Aug 12 2009, 12:50 AM

A couple of questions. Given how nicely the first results from Kepler have turned out, should it be possible for Kepler to:

a] detect almost-but-not-quite transiting hot Jupiters from the rising and falling phase-induced light curves (i.e. like HAT-P-7b only without the transits).

b] detect the presence of other, non-transiting planets from variations in the timing of the transits of planets they can see?

Posted by: Hungry4info Aug 12 2009, 08:37 AM

Yes. The inclination will still be unknown, but constrained as a function of the light curve variation, and models of the planet's reflectivity. I would expect such things to not really be noticed though. I don't know how the Kepler software works. If it's anything like some others, transit-like dips in brightness get flagged as planet candidates, and then examined more closely. You might imagine that a planet detection like one you describe would easily be assumed to be intrinsic stellar variability. (unless it holds up for a very long time, which would indeed be the case if it's a planet. In that event, it all depends on if it's noticed or not. Then the next obstacle is whether or not to devote resources to follow-up on it).

Yes. What really helps is that the planets that Kepler detects will have many, many transits measured, and in high-detail for the bright stars. A long baseline is crucial in detecting transit timing variations. Kepler is uniquely situated to do this, more so than CoRoT due to a longer observation time in a fixed point in the sky.

Posted by: Greg Hullender Aug 12 2009, 04:55 PM

Yes, Kepler will detect non-transiting, close-in Giant planets.

"The Kepler Mission readily records the modulation of the light reflected by about 870 close-in giant planets as their phases change between superior and inferior conjunction."

http://kepler.nasa.gov/sci/basis/giants.html

In this case, "close-in" means a period of a week or less.

--Greg

Posted by: Gsnorgathon Aug 12 2009, 11:23 PM

But only if they're close in. For planets in Earth-sized orbits, they'd only have 3 or 4 transits during the course of the primary mission. (Or would 3 - 4 transits be enough to detect variations in timing due to other planets?)

Posted by: Greg Hullender Aug 12 2009, 11:59 PM

Four transits is probably enough to determine that there ARE other planets, but I'd be very surprised if you could usefully extrapolate much of anything about them. Too many variables and not enough data points.

Posted by: illexsquid Aug 14 2009, 10:53 PM

Thanks for the link back to moons... saved me the trouble of searching. There's something that's I've been thinking about regarding moon detection with Kepler data.

Most investigators seem to be focusing on the transit-timing method for detecting moons: the slight advance or delay of transit ingress and egress due to motion of the planet around the planet-moon barycenter. This timing variance will be slight, but within the edge of detectability. I also saw one reference to the possibility of slight additional dimming before or after the main transit due to the physical body of a large moon. For this to be possible, the moon will have to be very large indeed, approaching Earth diameter: much larger than Ganymede, but within the realm of conceivability.

For a moon this size, a possible third method of detection occurs to me. The Hill spheres of hot Jupiters are very small, so that even a moon in a high-inclination orbit is likely to transit and be occulted by its planet as seen from Earth (or Kepler). Also, it is likely to have a very short period even relative to the abbreviated "year" of the hot Jupiter, probably on the scale of hours. Won't we therefore see a signal as the moon passes in front of and behind the planet during transits? This signal will be much fainter than the main transit signal, of course, but shouldn't it be possible to tease it out? Over the course of time, as the number of observed planet-star transits increases, the observed moon-planet transits will increase at some multiple, enabling characterization of both the moon and the planet. Especially coupled with the barycenter/timing method mentioned above, this could tightly constrain masses and hence densities of exoplanets. Assuming, of course, that such moons exist.

I'm sure someone must be working on this; has anyone more familiar with the literature or the community seen or heard a mention?

Posted by: stevesliva Aug 15 2009, 05:14 PM

Won't the transiting moon always be in eclipse? Do you mean you might see signal from a moon when it is not transiting its planet? (And therefore is neither in front or behind the planet and is transiting the star?)

Posted by: illexsquid Aug 15 2009, 11:21 PM

Yes, Steve, that's what I mean. I suppose it depends on what you mean by "signal," but the indication of the presence of a moon would be the magnitude difference between the star transited by both planet and moon and the the star transited only by the planet, because the moon is transiting the planet or being occulted by it. In my quick-and-dirty illustration (not to scale), on the left the star is transited by both star and moon, but on the right, the moon has moved in front of the planet as it tranits, resulting in slightly less occultation of the star. Is that clearer?

Posted by: stevesliva Aug 16 2009, 12:50 AM

Yup. Makes sense. And I of course won't pretend to know whether it's detectable, but part of me thinks that if they see the temporal shifts between planet transits, they'll be on the lookout for amplitude wobbles as well.

Also, though, as the planet/moon gets farther from the star, you might just get two or three separate transits.... what would Jupiter+Callisto or Saturn+Titan look like 200 light years away? Do they resolve as separate transits?

Posted by: dvandorn Aug 16 2009, 01:52 AM

I'm not sure what you mean by "resolvable," Steve. It's not like we're able to resolve a star disk image with a transit visible as a blotted-out circle within it. But I would imagine that the "resolution" in this regard would be the same as Kepler's overall ability to detect a planetary transit. A moon would have to be the minimum size necessary for Kepler to detect it, all by itself, as a transit event. So if Kepler can't detect the dimming of a star's light caused by the transit of a Callisto-sized planet, it ought not be able to detect the additional dimming that would occur with a Callisto-sized moon as it would appear in the first frame of 'squid's excellent illustration. And also, therefore, ought not be able to tell the difference between the first and second frames.

As I understand it, Kepler can detect down to about an Earth-sized planet, correct? Then I would have to think that the smallest gas giant moon it might detect would have to be at least as large as the Earth.

Another very interesting thing, though -- any planetary body with a ring system will block more or less of a star's light depending on the angle the ring plane presents to the viewer. I can well imagine that some percentage of the planets Kepler will discover may indeed have ring systems, and that these ring systems may not always present the same angle to us here on Earth during every single transit. It will be very, very interesting to see how fast the investigators suspect they're seeing ring systems in some of their results...

-the other Doug

Posted by: illexsquid Aug 16 2009, 05:23 AM

I think "resolultion" in this case refers to time. According to the mission website, Kepler samples a star's brightness every fifteen minutes. I don't know how long a typical Kepler transit will be but in the http://xxx.lanl.gov/abs/0907.5150 the transits ranged from an hour up to sixteen hours, with perhaps three hours being the norm. So if we assume a transit takes three hours, we have only about a dozen samples per transit. That is a pretty small sample size from which to try and weed out moon data, and it is a reasonable question whether it will be possible. It seems to me that, if we have a particularly long, slow transit (say 8 hours), an unusually large moon (approaching Earth sized or at least larger than Mars), and a bit of luck, it will be possible, but won't be obvious in the raw data. However, over time Kepler will obviously accumulate observations of multiple transits for each planet detected by Kepler, so that with rigorous analysis it might be possible even with less extreme examples. This is more believable after seeing how clean and noise-free the data were at the Aug. 6 news conference.

As for a ring: Doug, I hadn't thought of it, but it will obviously wreak havoc with density assumptions at first, as first contact of the rings will be difficult to differentiate from the planet itself, giving a grossly inflated diameter estimate. I imagine the difference will become apparent over time, as more samples are added to the data set, but in the meantime someone will publish a paper they'll have to retract.

Posted by: helvick Aug 16 2009, 06:54 AM

Hmmh - it seems to me then that a number of the extremely low density exoplanets already discovered might actually have ring systems, it's just that we have (as yet) no mechanism (other than a very low apparent density) for making that case. I'm specifically thinking about such oddities as TrES-4 (1.67 Jupiter radii but 1/6th the density) although from the discussions I've seen so far the smart money on all of these appears to be on tidal heating.

Although this does also get me thinking that surely it would be nearly impossible for any large moon ( certainly anything earth sized ) or significant ring system to survive around any of the hot Jupiter class of planets? Tidal forces would be immense and since the numbers indicate these are probably enough to inflate the Hot Jupiters by 10-20% in any case then surely they would be more than enough to rip any significant moon apart and lead to environments far to chaotic for rings to form? Or is there a possibility for a class of "Trojan\Greek" style co-orbital dust clouds rather than rings that might be more stable in such an aggressive environment?

Posted by: Hungry4info Aug 16 2009, 07:07 AM

Yes, they would be able to detect the transit of a sufficiently large moon separate from the planet, regardless of if the two are transiting simultaneously, just so long as the planet doesn't eclipse or occult the moon at the time of transit (in which case, surely, it won't in at least some other transits).

Normally, yes, but with the transit light curve of a planet being scrutinsed, that photometric data gets much more attention. Photometric data containing evidence for a planet (one of the later OGLE planets) went un-noticed for quite some time. Kepler and others like it gather a lot of data, which isn't too easy to sift through easily and detect very minute transits. I hope they intensely scrutinize Kepler photometry around transits of medium and long-period planets in search of moons. Though I don't know what you could really say about them (other than their radius, with a significant error) without extensive transit-timing observations (Hey, Kepler might give those too).

Did you see the depth of the HAT-P-7b secondary transit in the raw data during the press release? It's apparently the same depth as an Earth-radius planet in transit. It shouldn't be much of a stretch to imagine a transit depth half of that (not half the radius of the planet, of course, but a planet whose disk has half the 'area').



This paper,

Transit Detectability of Ring Systems Around Extrasolar Giant Planets
http://arxiv.org/abs/astro-ph/0409506

discusses the transits of ringed planets, shows example light curves, and describes how scattering may allow for one to determine the size of particles in the rings.

Posted by: Reed Aug 16 2009, 07:40 AM

Earths in both size and orbital period, meaning only three transits over the Kepler mission. With more transits, you can pull smaller planets out of the noise. The Kepler site has some information http://kepler.nasa.gov/sci/basis/sizes.html

Posted by: tasp Aug 16 2009, 02:51 PM

So that I understand, are you asking about detecting various Trojan objects sharing the orbit of the 'Hot Jupiter' around the star ? Does anyone recall the maximum mass a Trojan object can have (seems like I recall mass ratios affecting Trojan stability) and does that overlap with what Kepler might be able to detect ?


Fascinating contemplating what might (and might not) turn up in this missions results.

Posted by: Greg Hullender Aug 17 2009, 01:47 PM

In the usual formulation, the medium body must be at least 25x smaller than the large one, and the smaller body must have "negligible" mass. I'd be surprised if even a moon-sized object were stable even with a 10x Jupiter, but someone would probably have to simulate it numerically to know for sure.

--Greg

Posted by: PhilCo126 Aug 17 2009, 03:52 PM

Well, I've read that for a distant observer, a Jupiter transit would have a duration of 30 hours, a Saturn transit about 40 hours...
Exo-moons could be detected with more accurate detectors, , a Planet-Moon system would have a characteristic transit timing variation, for instance a Jupiter-Europa system would have a variation in the order of 10 seconds, a Saturn-Titan system in the order of 30 seconds...
Ring system might be easier to detect

Posted by: illexsquid Aug 18 2009, 08:51 PM

By "transit timing variation," are you referring to delays or advances in the transit time due to the planet's motion around a planet-moon barycenter? This is the method described in the discussion earlier in the thread. It would seem to me that, in order for such a system to be detectable with Kepler, the moon would need to be more massive, relative to the planet. We've found larger planets than Jupiter; it's only reasonable to assume that larger moons than Ganymede also exist. And such larger moons--if they indeed exist--could be detectable by their own transits across the star as well, I should think, especially if their presence was already suspected from the timing data.

Helvick's concern about the stability of moon orbits for hot Jupiters due to tides is notable, but again, if we tweak our hypothetical we might avoid it. Wouldn't there be more available stable orbits for a large moon of a planet in a 24-day orbit than of one in a 3-day orbit? As a bonus, the 24-day planet will have lower orbital speed and thus a longer transit, giving a longer sample of planet-moon interaction.

I haven't heard anyone talk about work on direct detection of moons transiting their planets. Any graduate students looking for a thesis idea?

One other possible source of noise occurs to me; it's also an opportunity for stellar studies, I suppose. If a planet crosses a large starspot, the variation in total light will be similar to its eclipsing a large moon. There are of course differences; the region surrounding a starspot is usually brighter than the average star surface, no? Has such an event been modeled? What would the resulting light curve look like?

Posted by: Mongo Aug 19 2009, 12:50 AM

Another possibility is stellar flares during a transit, which in fact have been detected:

http://arxiv.org/abs/0908.2329



Bill

Posted by: Greg Hullender Aug 19 2009, 09:43 AM

From reading the Kepler site, I think several of these questions have easy answers. The short summary is that it'll probably find Earth-sized moons in Europa-sized (or bigger) orbits but only if the primary planet has a one-year period AND if the moon orbits in the same plane as the planet (so that they both transit the star).

If the satellite is Earth-sized, then when it transits the star, it should show the same light-curve effect as any Earth-sized planet. Depending on how large the orbit is, that transit may or may not overlap the transit of its primary. If the big planet has a 1-year period, then Kepler should detect the satellite in much the same way as it detects any Earth-sized planet. If it has a longer period, then Kepler can't do it. If the satellite is only Ganymede-sized, then the primary would need to be much closer to the star, raising questions about whether satellites have stable orbits -- other than orbits SO close that Kepler can't see them.

Another point no one has mentioned is that this only works if the orbital plane of the satellite is close to the plane of the primary's orbit. Otherwise we'll miss the transit in all probability. That makes Jupiter a better bet than Saturn (other than the need for a 36-year mission, of course.)

Observing moons transiting planets (but not transiting stars) is clearly beyond Kepler's capabilities, since Kepler is barely able to measure the effect of reflected light from a giant planet in a one-week orbit. The light-change from full to crescent is a LOT bigger than the smaller change when a moon transits.

--Greg

Posted by: tasp Aug 19 2009, 01:16 PM

Just pondering other possible 'yon wee beasties' Kepler may or may not detect, has anyone considered a light curve for a binary 'hot Jupiter' orbiting a star?

I'm not sure how stable a double planet might be in this regard, but if the twins orbited their barycenter in a multiple of their period around the host star maybe we might have a stable situation ?

Posted by: Hungry4info Aug 19 2009, 11:21 PM

No one can say for 100% certain that its impossible, but none have been identified yet. It's quite possible that some of the non-transiting Jovian planets known today are actually double planets, we wouldn't know with just radial velocity alone.

If a double planet transited, it would be pretty much the same dynamics as a planet + moon transit, but the transits would be more similar to each other.

Posted by: Greg Hullender Aug 20 2009, 12:16 PM

This is the three-body problem again, of course. Someone would probably need to do some heavy-duty numerical simulations to find out whether any such combination is "stable" in the sense of "neither body gets thrown into a different orbit nor do they collide." My guess is that they'll eventually collide unless they are very far from their star.

If they orbit far enough apart, Kepler certainly out to see a two-step phase curve -- even if the pair really were far from the star and Kepler only got to witness a single transit. Of course, a single transit wouldn't eliminate the possibility that two planets in different orbits just happened to transit at the same time. Still, in a few years, we'll have a much better idea whether such things do exist in any numbers.

--Greg