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Unmanned Spaceflight.com _ Telescopic Observations _ WISE

Posted by: ngunn Aug 27 2009, 08:31 PM

I'm used to reading excellent articles by Emily, but this one I found to be of truly extraordinary interest:

http://www.planetary.org/blog/article/00002070/

Posted by: Gsnorgathon Aug 27 2009, 11:37 PM

Yes. And the funny thing is, my mind was being all boggled by the implications of the mission, and then I got to the bit about 15kg of solid hydrogen. Holy cow!

Posted by: Mongo Aug 27 2009, 11:46 PM

I wonder why they chose solid hydrogen instead of liquid helium for the coolant. My best guess would be that the mass of the helium tank would be too great for the WISE mass budget (the Herschel spacecraft seems to be basically a giant liquid helium tank with attached optics and electronics), plus liquid helium might be slightly overkill for the wavelengths it will study.

Bill

Posted by: stevesliva Aug 27 2009, 11:48 PM

Is it harder to control the torques from Liquid Helium? Does it slosh a little more an fight gyros?

Posted by: ngunn Aug 28 2009, 10:35 AM

A handy free article on solid hydrogen:

http://www.tvu.com/PEngPropsSH2Web.htm

Posted by: Juramike Aug 28 2009, 02:36 PM

"macroscopic crystals characterized by different nuclear spin states"

Whoa! This takes Pasteur separating chiral crystals to a whole new level. That is just plain bizarre!

Posted by: elakdawalla Aug 28 2009, 04:11 PM

QUOTE (Mongo @ Aug 27 2009, 03:46 PM) *
I wonder why they chose solid hydrogen instead of liquid helium for the coolant. My best guess would be that the mass of the helium tank would be too great for the WISE mass budget (the Herschel spacecraft seems to be basically a giant liquid helium tank with attached optics and electronics), plus liquid helium might be slightly overkill for the wavelengths it will study.

Bill

Sounds like you're right, and there's one other advantage. From Bill Irace: "Our detectors do not require He temp (1.5 K) and solid Hydrogen (6.5 K) has about 7X the specific heat as liquid He: ergo lower weight system."

--Emily

Posted by: nprev Aug 28 2009, 07:18 PM

Huh. I'd always thought that hydrogen needed to be highly pressurized to freeze; guess I was confusing that with what's needed to achieve its 'metallic' phase. Pretty ingenious, and as you said in your blog, Emily, this looks to be an exciting mission!

Posted by: SteveM Sep 3 2009, 03:15 AM

I know it's really premature to begin talking about what to do after WISE sublimates all it's solid hydrogen before it's even launched. Nonetheless, I imagine there must be some contingency planning for a WISE warm mission analogous to that of Spitzer. See the discussion of Spitzer beginning at this link.

Among the things http://www.nasa.gov/mission_pages/spitzer/news/spitzer-20090506.html is the detection of asteroids during the Spitzer warm mission. WISE warm might be able to continue its asteroid survey.

Steve M

Posted by: PhilCo126 Oct 27 2009, 07:24 PM

Wide-field Infrared Survey Explorer
WISE preparation for launch from Vandenberg Air Force Base ;
http://mediaarchive.ksc.nasa.gov/search.cfm?cat=216
Launch scheduled 7th December 2009

Posted by: dtolman Nov 12 2009, 04:54 PM

The latest Sky and Telescope has a nice article on this - I was astonished that they gave even odds to finding a brown dwarf CLOSER than Alpha Centauri.

Posted by: Greg Hullender Nov 12 2009, 09:54 PM

QUOTE (dtolman @ Nov 12 2009, 08:54 AM) *
I was astonished that they gave even odds to finding a brown dwarf CLOSER than Alpha Centauri.

Given that smaller stars are more numerous than larger ones, I'd have thought it almost a certainty they'd find a number of brown dwarves closer than Alpha Centuri. What I'm wondering is whether a brown dwarf inside the Oort Cloud might be responsible for otherwise-difficult-to-explain things like the orbit of Sedna.

--Greg

Posted by: ngunn Nov 12 2009, 10:26 PM

I'm somewhere between evens and 'almost a certainty' but I agree that their statement of the odds is probably on the cautious side of what they are actually thinking. I say this because they will be able to detect objects below the small end of what we normally think of as brown dwarfs.

Posted by: nprev Nov 12 2009, 10:31 PM

I too wouldn't be surprised if there were one or more brown dwarfs closer than the Alpha Centauri system. However, I'm also pretty confident that orbital anomalies in the extreme outer Solar System could just as easily be explained by the nearby passage (within 1 light-year) of stars and/or brown dwarfs, which has doubtless happened more than once over geological time.

Would definitely be interesting if we do have a very nearby neighbor, though. Might take decades of observation to determine whether such an object was just passing by or actually associated with the Sun.

Posted by: Greg Hullender Nov 13 2009, 04:21 AM

I suppose I should say that, after LCROSS and the mystery of the incredible plume, I'm all in favor of NASA making conservative predictions but being prepared to record spectacular results.

It's funny; there's not a lot of buzz about WISE, but between brown dwarves and optically-dim Earth-crossing asteroids, it promises to deliver an incredible wealth of information.

If they manage the extended mission, they'll have two shots of each object, six months apart. Since their resolution is 2.75 seconds of arc per pixel, that ought to give them a good clue as to which objects at least MIGHT be associated with the sun. Too much or too little change in position would mean it's either going to fast or located too far away.

--Greg

Posted by: PhilCo126 Nov 27 2009, 08:42 AM

Greg, the onboard frozen Hydrogen is expected to last 10 months, allowing WISE to map most of the sky a second time in order to see what has changed. So only a partial 2nd survey should be possible...
Launch is now set to 9th December smile.gif

Posted by: Greg Hullender Nov 27 2009, 06:48 PM

I guess I'm counting on even that number having some safety factor in it. :-)

Something else I've thought about recently is that two observations six months apart aren't enough to characterize an orbit. Even if it finds thousands of new asteroids, the fact that we can't observe them from the ground seems to limit the immediate usefulness of the data. Or perhaps it's hoped it could justify a followup mission a few years later? Or maybe just offer good initial targets for Pan-STARRS.

My personal hope is still that it finds a brown-dwarf companion to the sun that offers some explanation for things like the orbit of Sedna and the abrupt edge of the Kuiper belt -- not to mention a REALLY great flagship mission target. And even if not, WISE ought to be able to absolutely rule out the possibility of such a thing.

We're probably still a good year away from any results, I guess. Unless they really DO find that brown dwarf.

--Greg

Posted by: ngunn Nov 27 2009, 10:22 PM

When is a brown dwarf a black dwarf? When it no longer emits any visible light at all? If they find any of those nearby I think Herschel will be on the case.

Posted by: nprev Nov 27 2009, 10:39 PM

I always thought that a black dwarf was a completely burned-out star, normally a former white dwarf...considerably more massive than a brown dwarf.

Posted by: ngunn Nov 27 2009, 10:56 PM

Probably right. I just wanted to make the point that WISE could discover objects close to room temperature. Would it really be appropriate to call them brown dwarfs? If the term 'black dwarf' is to be confined to cooled white dwarfs then we need a new name for cooled brown dwarfs and other objects that were never even hot enough to be brown for any length of time but could still turn up in IR surveys.

Posted by: Reed Nov 28 2009, 12:14 AM

QUOTE (Greg Hullender @ Nov 27 2009, 10:48 AM) *
Something else I've thought about recently is that two observations six months apart aren't enough to characterize an orbit.

Existing and future narrow angle instruments should be able to follow up on them. You'd never get Herschel, Keck or VLT time for a large area survey, but they are definitely candidates for followup.

Posted by: PhilCo126 Nov 28 2009, 10:34 AM

It isn't just two obsevations six months apart;
There’ll be sufficient overlap, so that each position in the sky gets eight or more independent exposures on successive orbits. wink.gif

Posted by: nprev Nov 28 2009, 10:48 AM

Thing is, what if we have a companion brown dwarf about a 0.5 LY out with an orbital period of 100,000 years or so? Finding such a thing should be easy with WISE, but it may take a decade or more to confirm that it's probably in orbit around the Sun, even longer to derive a decent ephemeris. The problem isn't frequency of observation, it's very low orbital velocities for distant objects.

New Horizons is still trying to work out ephemeris uncertainties for Pluto because it hasn't been observed for even half an orbit since its discovery.

Posted by: Greg Hullender Nov 28 2009, 06:52 PM

Proxima Centauri is 0.21 ly from the Alpha A/B barycenter, and even after 100 years, we're still not QUITE sure it's actually orbiting the other two.

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

I'd hope we'd do a BIT better with an object nominally orbiting our own sun, but it'd still take a while. Even with the overlapping observations, I think the trouble with the WISE data will be that it spans just one year. Of course, something that barely moves after one year (like a remote brown dwarf) probably won't get lost easily, but an Earth-crossing asteroid might well be hard to find again.

As for black dwarfs, the Universe probably isn't old enough for any to exist yet:

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

There are already known brown dwarfs with estimated temperatures as low as 500K:

http://en.wikipedia.org/wiki/Brown_dwarf#Distinguishing_low_mass_brown_dwarfs_from_high_mass_planets

It seems plausible that smaller, cooler ones exist and even might be more plentiful than regular stars, given the mass/frequency curve we seem to see everywhere else in the universe. WISE could well find LOTS of brown dwarfs closer to the sun than (say) 4 light years.

I guess we'll know in eighteen months or so!

--Greg



Posted by: NGC3314 Nov 29 2009, 04:03 AM

If the IR broadband signature for brown dwarfs really is distinctive enough, candidates can be followed up with large ground-based telescopes once WISE points them out. That would give much higher angular resolution as well as time baseline. One of the bumper-sticker descriptions of WISE (back when it was NGSS, which someone thought would be too confusing compared to NGST which is now JWST) was that it should discover both the most luminous galaxies and our nearest stellar neighbors; practically something for everybody.

Posted by: DFinfrock Nov 30 2009, 06:24 PM

QUOTE (Greg Hullender @ Nov 28 2009, 06:52 PM) *
WISE could well find LOTS of brown dwarfs closer to the sun than (say) 4 light years.


I can't wait to begin the exoplanet surveys for all of those local brown dwarfs!

David

Posted by: PhilCo126 Dec 10 2009, 10:31 AM

Launch postponed: The WISE launch is currently scheduled for no earlier than Saturday, December 12th, at 6:09:33 am pacific, from Vandenberg Air Force Base in CA...

Posted by: ElkGroveDan Dec 10 2009, 03:36 PM

...and even that doesn't look likely at this point.

Posted by: Holder of the Two Leashes Dec 10 2009, 11:32 PM

We might want to lower our expectations just a bit for finding brown dwarfs closer than Proxima. There is a distinct possibility for finding none at all.

Posted by: ElkGroveDan Dec 11 2009, 01:05 AM

At least not until after it launches anyway. Which is now set for Sunday the 13th. I'll miss that one, but if it gets bumped over to Monday or Tuesday I might be able to make it again.

Posted by: Vultur Dec 11 2009, 06:16 PM

If there actually is a close brown dwarf, that would be so interesting...

Posted by: nprev Dec 11 2009, 06:41 PM

Launch now set for 1409-1423 GMT on the 14th (0609-0623 PST.)

Posted by: ElkGroveDan Dec 12 2009, 03:20 AM

Yep Monday now. It looks like I might get a tour of the actual launch pad Sunday night. Stay tuned. I might also be blogging it on well-respected site. Although it is still raining like crazy down in Southern Cal where I am now.

Posted by: nprev Dec 12 2009, 03:31 AM

Do tell, now! smile.gif MOST cool; looking forward to some on-site reporting!

Posted by: Greg Hullender Dec 13 2009, 02:52 AM

These postponements worry me because they've already packed the solid hydrogen, so every day of delay is probably costing us a least a day (maybe more) of mission time.

--Greg

Posted by: nprev Dec 13 2009, 03:15 AM

I was thinking that, too, but logically there has to be some sort of cooling in place till just before launch; certainly the possiblity (even probability) of a delay on the pad had to be considered even during early planning. That stuff wouldn't last long at all even in a Dewar vessel in terrestrial ambient conditions.

Posted by: elakdawalla Dec 13 2009, 04:33 AM

If I recall correctly from my conversation with them, they re-run the chilling routine every other day. So every other day you reset the clock on the frozen hydrogen. Which means that if you're the science team you really want the spacecraft to launch on that first rather than second day. I would imagine that with the weekend's delay, Monday will be "day 1" of that cycle.

Also, I just remembered that the chilling routine involves a team of poor guys whose sole job is to run those tanks of liquid helium up the tower to the top of the rocket, where the spacecraft is, remove the old tank, hook up the new tank, run the old tank down to the bottom of the tower, and repeat.

Posted by: nprev Dec 13 2009, 04:38 AM

Thanks, Emily. Figured there had to be something; didn't think that it'd be pretty! sad.gif

Posted by: elakdawalla Dec 13 2009, 04:49 AM

I think those kinds of details are funny. It's amazing all the weird, different ad-hoc solutions it takes to get each unique spacecraft launched. I smirk every time I see the enormous backshell for MSL, because it has a monster hatch (big enough for Buzz Aldrin to fit through) that had to be cut into it so they can install the RTG on to the rover's butt at the very last opportunity before launch, while the spacecraft is stacked on top of the rocket on the launch pad. And they have to have three redundant air conditioning systems in the assembly tower because if things fail, that RTG will heat everything up in a hurry. Every mission has weird stuff like this. It's not like sticking your laptop on top of a firecracker and booting it up after it's safely in orbit -- each spacecraft has to have something difficult even before you launch it.

Posted by: nprev Dec 13 2009, 05:02 AM

Ooooh, yeah. smile.gif Space systems engineering itself is a black art, really. Each & every SV is really a creation unique unto itself with at least one quirky little piece of impromptu ingenuity that turns out to be vital to making the whole mission succeed. Gotta love these people!

Posted by: ugordan Dec 13 2009, 12:15 PM

Not to mention it's requirements like that - late/specific access to the payload and custom mods to the vehicle/pad that drive launch costs up. Not that they're not already significant... rolleyes.gif

Posted by: ElkGroveDan Dec 13 2009, 05:30 PM

It's been raining like crazy for the last couple days, and still is, but it looks like tomorrow morning is going to be clear out on the coast. I think we're pretty much GO for 6:09 am Monday Pacific Time. Crossing my fingers on getting out of here in time today to make it over there.

Posted by: elakdawalla Dec 13 2009, 06:01 PM

Weather in L.A. was spectacular this morning. Bright clear blue sky and sun. Rain? What rain? Go WISE!

Posted by: scalbers Dec 13 2009, 06:52 PM

QUOTE (ngunn @ Aug 28 2009, 10:35 AM) *
A handy free article on solid hydrogen:

http://www.tvu.com/PEngPropsSH2Web.htm


Here's a photo of solid hydrogen floating on liquid helium...

http://www.grc.nasa.gov/WWW/RT/RT2002/5000/5830palaszewski2.html

Posted by: centsworth_II Dec 13 2009, 07:19 PM

QUOTE (elakdawalla @ Dec 12 2009, 11:33 PM) *
...I just remembered that the chilling routine involves a team of poor guys whose sole job is to run those tanks of liquid helium up the tower to the top of the rocket...
Here's an interesting blog on the subject: http://www.cosmicdiary.org/blogs/nasa/amy_mainzer/?p=519
"...our valiant Utah cryo crew worked right through Thanksgiving. Our project managers brought Thanksgiving dinner and all the trimmings up to the crew at Vandenberg. Of course, they weren’t allowed to bring pumpkin pie into the cleanroom on top of the tower with WISE and the rocket, but they got to have a little bit of holiday cheer. Thanks, cryo crew!"


Hopefully they'll be home for Christmas!

Posted by: NGC3314 Dec 13 2009, 07:59 PM

QUOTE (elakdawalla @ Dec 12 2009, 10:33 PM) *
I just remembered that the chilling routine involves a team of poor guys whose sole job is to run those tanks of liquid helium up the tower to the top of the rocket...


Something similar happened with ESA's ISO far-IR observatory (pardon the redundancy with the acronym). A team had to head out to check something on the Ariane 4 booster well after the area would normally be cleared, and one of the payload teams took the opportunity to head out at the same time and top off its liquid helium dewar. With the boiloff from external conditions in French Guyana, scuttlebutt was that this added a few months to the cryogenic mission lifetime (something like 27 months of an expected 24 and required 18).

Posted by: climber Dec 14 2009, 03:08 PM

Wise has been succesfully deployed in orbit

Posted by: ElkGroveDan Dec 14 2009, 04:28 PM

Yes indeed. And I missed the launch mad.gif

Can't wait for the science results to start coming in.

Posted by: maschnitz Dec 14 2009, 07:54 PM

Here's a general "mission/science expectations" summary post, since I was curious, and I had to dig around a bit to get it:

Emily http://www.planetary.org/blog/article/00002255/, "There's a one-month commissioning phase before science starts. ... The main imaging instrument gets turned on in five days. Sixteen days after launch, the cryostat cover will be blown off. Then there are two weeks of checkouts of instruments and systems, followed by a nine-month nominal mission. That nine months will allow them to perform 1.5 complete sky surveys."

There's one sky survey in six months because it's in a sun-synchronous orbit and thus WISE hits both sides of the sky in its orbit (obviously), and it scans the skies by waiting for Earth to orbit the Sun.

Space.com http://www.space.com/missionlaunches/091214-nasa-wise-launch-wrap.html that "WISE will capture about 5,700 pictures a day of the infrared sky. The mission management team says it will release the first science data within one month of launch."

And one of the project scientists said in the press conference that they'll be announcing interesting objects as they spot them. But the bulk of the data will be released in two big chunks at the very end of the mission - first release, April 2011, second, March 2012, according to http://www.astro.ucla.edu/~wright/WISE/.

In case it's not obvious: I think this mission is very exciting. Congrats to NASA on a successful launch!

Posted by: centsworth_II Dec 23 2009, 06:56 AM

For those who like observing things in orbit:

I've pasted the entire post here.

http://cosmicdiary.org/blogs/nasa/ned_wright/?p=55
"WISE is now in the Heavens Above orbit database. It will be favorably placed over Los Angeles on the morning of Dec 24, and I will try to observe it. You can get predictions for you own location from Heavens Above and try to spot it. If you try leave a comment describing your observation." -- Ned Wright, WISE PI

Posted by: belleraphon1 Dec 30 2009, 01:52 AM

NASA's WISE Space Telescope Jettisons its Cover12.29.09
http://www.nasa.gov/mission_pages/WISE/news/wise20091229.html

WISE is scheduled to begin its survey of the infrared heavens in mid-January of 2010.

Really looking forward to the asteroid, brown dwarves results. And the unexpected!

Craig


Posted by: nprev Dec 30 2009, 02:03 AM

Always a relief to hear that the last critical deployment event for a mission was successful! smile.gif

Here's to seeing the unexpected...we always do.

EDIT: First guess at the unexpected: Spotting the Solar System's "debris trail". Given the fact that matter is pretty sparsely distributed in interstellar space, there should be a fairly constant escapement of micron-sized dust along with all kinds of molecular species that should stand out by contrast.

This outflow of course would be strongly influenced by the heliopause & other effects...but it would be interesting & scientifically useful for many reasons if it could be observed & characterized.

Posted by: alan Jan 6 2010, 10:24 PM

First light

http://wise.ssl.berkeley.edu/gallery_first_light.html

Posted by: centsworth_II Jan 7 2010, 03:57 AM

"More soon, including a comparison of this new WISE image vs. the old catalogs it will replace: COBE and IRAS."
http://www.cosmicdiary.org/blogs/nasa/amy_mainzer/?p=637

Posted by: belleraphon1 Jan 23 2010, 09:52 PM

Emily has posted the WISE news regarding the team's first asteroid discovery...

http://www.planetary.org/blog/article/00002316/

Exciting.... and open the WISE image... expand it and look at ALL those little red dots...lots and lots of little red (which means cool) dots.

http://www.planetary.org/image/PIA12499.jpg

Any brown dwarfs in there? I tremble!

Craig

Posted by: Floyd Jan 24 2010, 04:06 PM

Wow, there are lots of faint red dots in the image. However, I have a question on the number of asteroids Wise will find. If the nominal mission is 200 days, and is expected to find hundres or thousands of asteroids, then that is 1/day or 10/day for 200 or 2000 asteroids. From first light to first asteroid was 6 days---that is about 33 in 200 day mission. What am I misunderstanding?

Posted by: ngunn Jan 24 2010, 04:22 PM

The time lag due to the need for follow-up observations prior to announcement?

Posted by: Greg Hullender Jan 24 2010, 04:43 PM

Makes sense. Takes time to settle into a new routine, work out the bugs, fill the pipeline, etc. I'll repeat my concern that some of these objects will end up being hard to follow up on. Either because there are just too many for the available ground instruments or because they can't be seen from the ground at all.

But we'll see.

--Greg

Posted by: elakdawalla Jan 25 2010, 05:08 PM

There's interesting discussion of these issues going on in the http://tech.groups.yahoo.com/group/mpml/ by people who (unlike me) actually know what they are talking about in terms of astrometry and followup.

Posted by: Greg Hullender Jan 25 2010, 06:28 PM

Thanks, Emily. One post there, from Richard Kowalski with the Catalina Sky Survey at the University of Arizona seemed especially helpful.

http://tech.groups.yahoo.com/group/mpml/message/22940

In particular, he quoted Tim Spahr, Director of the Minor Planet Center as saying:

"It seems there is some information lacking that will help the understanding of the WISE mission a bit better. First and foremost, when fully operational, the spacecraft will observe each object ~10 times over ~1.0 days. Thus, each object observed will be of 'designatable' quality. Further, NASA has funded various projects to do follow-up specifically of their NEOs. At 1-2 new NEOs per day, there is an excellent chance that most NEOs will be followed-up with existing resources. Lastly, and this seems lost on nearly everyone, the existing follow-up capabilities are really staggering now. H55, G96, and 291 observe nearly every single new NEO discovered. It is really rather spectacular. So my feeling is really that WISE will probably not generate a big bunch of things with little or no information.

"On the MBA side, the MPC expects to link most WISE discoveries with observations from G96, 691 (also funded to support WISE directly), and 703. But even if we don't, there's nothing wrong with a bunch of 2-night objects in our files, waiting for other identifications at other oppositions in the future."

That pretty much answered my questions.

Thanks again!

--Greg

Posted by: lyford Jan 25 2010, 07:41 PM

QUOTE (Greg Hullender @ Jan 25 2010, 10:28 AM) *
H55, G96, and 291 observe nearly every single new NEO discovered.

Pardon my ignorance, but who are these numbers?

Posted by: elakdawalla Jan 25 2010, 08:42 PM

Those are observatory codes; if you read the MPECs you'll see the codes given next to the observations used for discovery and astrometry. There is a unique one issued to every telescope who does minor planet astrometry.

Posted by: ElkGroveDan Jan 25 2010, 08:49 PM

291 is the 1.8-meter Telescope of the Lunar and Planetary Laboratory, at Kitt Peak operated by the University of Arizona, Tuscon

G96 is a 60" reflector at the summit of Mt. Lemmon North of Tuscon

H55 consists of the 32" and the 24" telescopes at the Astronomical Research Observatory, Charleston. Illinois.

Posted by: Floyd Jan 25 2010, 08:59 PM

These post and links answer my questions as well. Followup on the WISE findings is complex and will involve lots of observatories--guess I wasn't the only one slightly confused by the initial reports--more information helps a lot.

Posted by: Greg Hullender Jan 26 2010, 04:53 AM

The best part, for me, anyway, is that they really do have a wise and well-thought-out plan for following up on all potential asteroid observations. Now I'm ready to sit back with some popcorn and watch the results come in!

--Greg

Posted by: lyford Jan 26 2010, 05:07 AM

QUOTE (Greg Hullender @ Jan 25 2010, 08:53 PM) *
Now I'm ready to sit back with some popcorn and watch the results come in!

One hopes we don't watch the asteroids come in.... laugh.gif

Thanks for the clarification Emily and Dan!

Posted by: Vultur Feb 10 2010, 02:28 AM

WISE has found its first new comet!
http://www.planetary.org/blog/article/00002337/


Posted by: avitek Feb 16 2010, 02:09 PM

QUOTE (elakdawalla @ Jan 25 2010, 10:42 PM) *
Those are observatory codes; if you read the MPECs you'll see the codes given next to the observations used for discovery and astrometry. There is a unique one issued to every telescope who does minor planet astrometry.


Full list of observatory codes can be found at http://www.cfa.harvard.edu/iau/lists/ObsCodesF.html

Posted by: SteveM Feb 18 2010, 03:18 PM

NASA has recently released a sample of the http://www.nasa.gov/mission_pages/WISE/multimedia/images20100216.html, showing everything from Comets to Galaxys.

Steve M

Posted by: Byran Mar 16 2010, 11:11 AM

http://wise.ssl.berkeley.edu/sky_coverage.html
More than 1/3 of the mission completed!

Posted by: Byran Mar 20 2010, 06:32 PM

I noticed that the north and south pole of its orbit satellite photographs over each period of around its orbit. I.e. two sites of the sky the total area of 1.28 square degrees to be obtained 4320 images. Do you plan to search for transiting planets in these data?
For comparison with the same area COROT field of about 2 square degrees, and time monitoring of up to 5 months.

Posted by: briv1016 May 14 2010, 07:55 AM

http://www.space.com/news/wise-space-telescope-extension-rejected-100513.html

Posted by: Greg Hullender May 14 2010, 04:36 PM

Well, I'm not sure how useful "Warm Wise" would have been anyway. It'd be nice to see how much they're finding in the four frequencies they have vs. the two they'd have left (after the hydrogen is gone).

I note they're 2/3 done with the first pass now.

http://wise.ssl.berkeley.edu/sky_coverage.html

Still no reports of brown dwarf companions to Sol.

--Greg

Posted by: Greg Hullender May 26 2010, 09:43 PM

Just past 75% coverage now.

http://wise.ssl.berkeley.edu/sky_coverage.html

No press releases since February 11, when they reported a new comet. Wonder why not?

--Greg

Posted by: Ron Hobbs May 26 2010, 10:55 PM

JPL posted a news item on Tuesday, http://www.jpl.nasa.gov/news/news.cfm?release=2010-176. There is an attendant video with an interview of the PI of NEOWISE, Amy Maisner, that is well worth catching. http://www.jpl.nasa.gov/video/index.cfm?id=905

According to the feature, 11,000 of the NEOs and asteroids it has observed are new.

Posted by: ElkGroveDan May 26 2010, 11:06 PM

QUOTE (Ron Hobbs @ May 26 2010, 02:55 PM) *
11,000 of the NEOs and asteroids it has observed are new.

ohmy.gif

Posted by: nprev May 27 2010, 03:38 AM

Yeah...what Dan said!!! blink.gif

That's absolutely mind-boggling. I was expecting a few hundred, maybe a thousand.

Posted by: ElkGroveDan May 27 2010, 04:55 AM

Does anyone know what the statistically predicted numbers of various classes of objects were, and how those numbers are shaking out thus far? Or will we have to wait for the "paper?"

Posted by: Stu May 27 2010, 05:26 AM

If we could see, with our own eyes, all the crap flying about Out There, we'd never dare look at the sky, would we..? ohmy.gif

Posted by: alan May 30 2010, 12:54 AM

WISE satellite already spots two brown dwarfs

QUOTE
One of the brown dwarfs, dubbed WISE 2, appears to be as cold as any that are known. It may even be colder, Wright said, than the brown dwarfs recently found by the UKIDSS survey, which are estimated to be in the neighborhood of 500 Kelvin, but the exact temperature of WISE 2 is uncertain (as are the temperatures of the UKIDSS objects). WISE 1 is a bit warmer, Wright said: "We think this is about an 800-Kelvin object."

Wright later said that whereas the spectra of WISE 1 and WISE 2 are unambiguous, the spacecraft has found many more objects that may also be brown dwarfs. Confirmation of those will await follow-up observations, which the group has proposed on the Spitzer Space Telescope. Distances to the two new brown dwarfs are not known, Wright added

http://www.scientificamerican.com/blog/post.cfm?id=wise-satellite-already-spots-two-br-2010-05-27

Posted by: centsworth_II May 30 2010, 11:58 AM

"....Wright said, than the brown dwarfs recently found by the UKIDSS survey, which are estimated to be in the neighborhood of 500 Kelvin...."

Just the right place to http://hypertextbook.com/facts/2003/SaraElzeftawy.shtml

Posted by: Greg Hullender May 31 2010, 02:57 AM

I'm surprised they don't have estimated distances to the Brown Dwarves. Much like Red Dwarves, I'd expect they must be fairly close to be visible at all, even by WISE.

--Greg

Posted by: nprev May 31 2010, 03:02 AM

Perhaps there hasn't been enough time yet to get good parallax observations on any of them?

Posted by: brellis May 31 2010, 03:05 AM

then, why is the mission nearly complete?

Posted by: nprev May 31 2010, 03:29 AM

Good point. We don't know when they were identified, though, nor if there have been any follow-up observations (presumably from ground-based assets.)

Given the limited operational lifetime of WISE I'll bet that they're in straight data acquisition mode all the way to the end, and sifting through the torrent is secondary at this point. There's probably no chance to take another look at almost anything.

Posted by: stevesliva May 31 2010, 05:33 AM

QUOTE (nprev @ May 30 2010, 11:29 PM) *
Good point. We don't know when they were identified, though, nor if there have been any follow-up observations (presumably from ground-based assets.)


Something actually mentioned [warm] Spitzer would be used to look at the Brown Dwarves.

Posted by: Greg Hullender May 31 2010, 04:32 PM

QUOTE (nprev @ May 30 2010, 07:29 PM) *
There's probably no chance to take another look at almost anything.

Except that asteroid observations have to be followed up on almost immediately. It does seem they're doing that.

I was interested that they hadn't found anything so dim in other frequencies that it couldn't be observed by some other instrument. That certainly suggests we ought to be able to get parallax measurements within a few months.

--Greg

Posted by: Holder of the Two Leashes Jun 22 2010, 11:55 PM

There have been some cases of follow up observations of asteroids being made months later (blast from the past), and a few cases of WISE making all the observations necessary by itself to designate an asteroid (WISE only). Also a very few cases of finding an asteroid only with WISE data months after the observations (2010 AR85 is an example). Here is the link to the asteroid discovery page at the WISE website.

http://www.astro.ucla.edu/~wright/WISE/WISE-MPECs.html Note that this is mostly for NEAs.

For parallax observations, WISE fortunately is always observing at right angles to the sun, so that even objects in the ecliptic plane will be observed at maximum angular displacement six months later. During the nine month mission about half the sky will be observed by WISE alone with parallax data points. Unfortunately, in most cases you will also need a data point at one year in order to subtract out the proper motion, which in most cases dwarfs the parallax. The mission will end after nine months. Follow ups will have to be with some other telescope.

Large proper motion itself might be the main indicator they are looking for, in order to find nearby objects (nearby in this case meaning stellar neighborhood).

A person at WISE outreach was kind enough to inform me that they can determine positional accuracy for stars to better than half an arc second. This is in line with the residuals I see listed on the asteroid reports from the minor planet center. So anything closer than, say, five or six light years should produce a measurable parallax, albeit with a fairly large error.

Posted by: Greg Hullender Jul 2 2010, 04:57 PM

I see WISE is past 95% coverage now, so definitely into the home stretch. I also noticed that they managed to analyze the blob around the Galactic Core which had given them some troubles earlier. It looks as though they had some sort of outage a month or so ago, meaning there's a small stripe that they missed. Since that's in the last half of the sky, that means it won't get reimaged on the second pass. Pity, but it's still pretty impressive.

I note WISE is up to 97 reported discoveries now.

http://neo.jpl.nasa.gov/stats/wise/

Including 13 Potentially Hazardous Asteroids (PHA). I don't see Torino numbers on any of these, so I'd guess there hasn't been time to analyze their orbits thoroughly.

--Greg

Posted by: Greg Hullender Jul 10 2010, 05:32 PM

With no special announcement, it seems WISE has completed its sky survey--minus those strips where the camera apparently went offline or something.

http://wise.ssl.berkeley.edu/sky_coverage.html

If wonder if there will be any big surprises during the next part of the mission, perhaps from noticing that something moved unexpectedly.

--Greg

Posted by: alan Jul 10 2010, 08:49 PM

I recall reading that the aim is changed to avoid the moon when is at first and last quarter. I suspect they get picked up the next time the moon reaches those phases.

Posted by: Greg Hullender Jul 17 2010, 01:47 AM

They updated the text on the page that shows progress. (Now at 99.5%)

http://wise.ssl.berkeley.edu/sky_coverage.html

They say the red stripes result from the moon-avoidance strategy. No mention of the off blue strip, but, somehow, they're covering it now, and they say they'll be at 100% tomorrow.

http://www.jpl.nasa.gov/news/news.cfm?release=2010-238

Some highlights:

more than one million images so far
more than 100,000 asteroids, both known and previously unseen
more than 90 new near-Earth objects
more than a dozen new comets
The first release of WISE data, covering about 80 percent of the sky, will be delivered to the astronomical community in May of next year.

Also today, they released a new pic of the Pleiades:

http://www.nasa.gov/mission_pages/WISE/news/wise20100716.html

Cool stuff!

--Greg


Posted by: Greg Hullender Jul 29 2010, 01:18 AM

The WISE coverage map has become much more colorful:

http://wise.ssl.berkeley.edu/sky_coverage.html

I wonder what the "16x" factor means? Does it actually mean that the point was imaged on 16 different orbits?

--Greg

Posted by: djellison Jul 29 2010, 01:51 AM

I would have thought so - notice the density increasing to the poles. It would have imaged, roughly speaking, the same spot over the north pole every single orbit just about

Posted by: Gsnorgathon Jul 30 2010, 12:35 AM

It's my understanding that folks looking for planets, comets, KBOs, &c. don't observe high above the ecliptic so much, because of the lesser likelihood of finding anything there. I'm curious to see if WISE manages to snag some interesting findings, especially since it's got so much polar coverage.

Posted by: ugordan Jul 30 2010, 12:40 AM

There should be a higher probability it will be a comet if they find anything there.

Posted by: elakdawalla Jul 30 2010, 03:51 AM

It's also a higher probability it's a NEO. With modest inclinations, if they're close enough, they'll still appear at high angles to the ecliptic.

Posted by: Bill Aug 1 2010, 07:48 AM

I find these informations on the comet section of British Astronomical Association, http://www.ast.cam.ac.uk/~jds/ :
Jul 23 WISE discovers asteroid in retrograde orbit
Jul 30 WISE discovers short period retrograde asteroid

Any more informations about these discoveries ?

Posted by: nprev Aug 1 2010, 08:11 AM

A short-period retrograde asteroid?

Wow. That might be the first such ever discovered, esp. if the orbit's anywhere close to the ecliptic plane. Hopefully more info will be forthcoming.

Posted by: Holder of the Two Leashes Aug 1 2010, 09:51 PM

The July 23rd discovery was asteroid 2010 OR1, which has a period about 30 years and an inclination around 143 degrees.

The July 30th discovery most likely was actually a reobservation of asteroid 2010 LG61, which was discovered by WISE back in June, but whose orbit at the time was nearly impossible to fit properly. They originally thought it was very small, in a prograde Aten type orbit. WISE got an additional look on the 26th which finally got the orbit right. It is a much larger rock than they thought with a period around 19 years (this is short period?) and inclined 123.7 degrees.

I can find no other candidate for the July 30th asteroid.

These are impressive, but not record holders. Other examples would be the recently discovered 2010 EB46, found by the Catalina Sky Survey back in March, which has a period 16.7 years and an inclination of 156 degrees, both of which best 2010 LG61. Then you have 2008 SO218, which beats out 2010 OR1 both on period (23 years) and on inclination, which is 170.4 degrees and nearly in the ecliptic going backwards.

Posted by: Gsnorgathon Aug 2 2010, 10:42 PM

Hey, thanks for blowing my mind, guys! I had no idea there were short-period retrograde objects. Is the basic idea that these objects started out as long-period retrograde comets and got herded into shorter orbits by Jupiter, or is there a more interesting story behind any of them?

(I note with great amusement that the first-discovered was named Dioretsa! [Retrograde? Dioretsa... think about it.])

Posted by: nprev Aug 2 2010, 11:20 PM

I am likewise impressed & enlightened, Holder! (Yeah, diggin' the name, Gsnorg... biggrin.gif )

Posted by: brellis Aug 3 2010, 03:23 AM

Dioretsa am I? I'm a asteroid! tongue.gif

Posted by: nprev Aug 3 2010, 03:32 AM

This thing's worth a mission just for the hours of nomenclature fun to be had mapping it. biggrin.gif

Posted by: Holder of the Two Leashes Aug 11 2010, 04:04 PM

WISE has depleted the coolant in one of its two tanks, and has begun warming up. One detector no longer functioning. All others working for now, and expected to work for some time.

http://wise.ssl.berkeley.edu/documents/WISE-CryoStatusReport-8-10-10%20(2).pdf?release=2010-238

Posted by: briv1016 Oct 4 2010, 08:49 PM

I guess WISE got its mission extension after all. I wonder what changed between these two updates.


http://www.space.com/news/wise-space-telescope-extension-rejected-100513.html

http://www.jpl.nasa.gov/news/news.cfm?release=2010-320

Posted by: stevesliva Oct 4 2010, 09:19 PM

I can't find anything more than you. It would seem the panel's decision wasn't executive.

Posted by: Greg Hullender Oct 4 2010, 11:53 PM

They realized their earlier decision was really unwise.

--Greg :-)

Posted by: ngunn Nov 10 2010, 12:46 PM

The brown dwarf harvest has begun. Emily has a post on it (which alerted me) but this article says more about the number already in the pipeline awaiting confirmation/publication, and the possible eventual total: http://www.spacedaily.com/reports/Cool_Star_Is_A_Gem_Of_A_Find_999.html

Posted by: Holder of the Two Leashes Jan 10 2011, 11:03 PM

Just a quick note in passing. WISE has completed the second survey.

http://wise.ssl.berkeley.edu/sky_coverage.html

Posted by: Greg Hullender Jan 11 2011, 02:40 AM

Wonder why no big announcement yet. Could it really be there's nothing closer than Proxima? Or does the analysis just take a lot longer than I imagine it should. (A common problem, I should admit.) :-)

--Greg

Posted by: Gsnorgathon Jan 11 2011, 08:35 PM

I've got a funny feeling that analyzing data from a survey that covers the entire visible (well, visible in IR) universe might just take a wee bit of time...

Not to mention that if you're going to announce that you've found a major astronomical object closer than Proxima, you really want to make sure you've got it right.

Posted by: Holder of the Two Leashes Jan 12 2011, 11:59 PM

Oooops(?).

It's possible I jumped the gun by a few days, I don't really know. I assumed that when the last dark blue streaks disappeared from the WISE coverage map, that would mean that the second survey was done. But it's possible that some high coverage areas from the first sky scan (which could show up as 16X+) have yet to have their six month checkup. If so, then we're still just a matter of days away from completion. The first survey ran from January 14 to July 17.

At any rate, here is the latest. There is going to be a public data release sometime in April. It will cover half the sky from the first survey. So, I expect that we may be hearing about some significant discoveries, if any, before then. Particularly if they are present in the area covered by the release.

http://wise2.ipac.caltech.edu/docs/release/prelim/preview.html

Posted by: NGC3314 Jan 13 2011, 04:31 AM

Ran into one of the WISE team and got a little more information on operations. Apparently, the warm mission extension was funded primarily to detect and characterize NEOs, and includes operations only through the end of January.

Posted by: Greg Hullender Jan 13 2011, 05:21 AM

I suppose at this point a fair question would be whether there would be any scientific value in an additional 6 or 12 months, given that the satellite is already in orbit and such.

--Greg

Posted by: briv1016 Feb 7 2011, 04:50 AM

http://www.jpl.nasa.gov/news/news.cfm?release=2011-031

Posted by: Greg Hullender Feb 7 2011, 03:11 PM

I see they're still planning for a public release of data (some of the data) in April, so if they've got a big announcement, they'll probably want to make it before that.

--Greg

Posted by: remcook Feb 11 2011, 08:15 AM

Freely accessible NEOWISE paper with a summary of discoveries so far and some nice comet pictures smile.gif
http://arxiv.org/abs/1102.1996

Posted by: alan Feb 17 2011, 07:02 PM

QUOTE
NASA's NEOWISE Completes Scan for Asteroids and Comets

Looking at fig. 3 in the paper I would say the scan for asteroids needed another 2 months to complete.

Posted by: djellison Feb 17 2011, 08:52 PM

The scan is complete. Read the figure caption:

QUOTE
The drop in density of objects observed near (+2, +2)
AU in the gure is due to the exhaustion of the secondary tank's cryogen on 5 August, 2010,
resulting in the loss of band W4.

Posted by: stevesliva Jul 19 2011, 12:04 AM

Some brown dwarf news:
http://news.discovery.com/space/could-ultracool-brown-dwarfs-surround-us-110718.html
referencing:
http://arxiv.org/abs/1105.4059

Large proper motion!

Posted by: hendric Jul 26 2011, 02:43 AM

How long before BrownDwarfHunters starts, eh? That would be an interesting project!

Posted by: maschnitz Jul 27 2011, 07:05 PM

WISE has found the http://blogs.discovermagazine.com/badastronomy/2011/07/27/wise-finds-the-very-first-earth-trojan-asteroid/. Neat!

Posted by: kto Jul 29 2011, 07:40 AM

NEAT didn't find it, WISE did!

Posted by: nprev Jul 29 2011, 07:52 AM

Great find! I think that the WISE dataset is gonna keep on giving for many years to come.

Posted by: Paolo Jul 29 2011, 05:06 PM

on the historical side, Earth Trojans had been searched since at least three decades http://cdsads.u-strasbg.fr/abs/1983BAAS...15..830D

Posted by: alan Sep 22 2011, 07:29 PM

WISE discovers 100+ brown dwarfs, including 6 Y-dwarfs, one with an estimated surface temperature of 80F.
http://www.nasa.gov/mission_pages/WISE/news/wise20110823.html

arxiv links
http://arxiv.org/PS_cache/arxiv/pdf/1108/1108.4677v1.pdf
http://arxiv.org/PS_cache/arxiv/pdf/1108/1108.4678v1.pdf


Edited to add.

Table 8 in the fist paper lists lower limits of the space density of various spectral types of brown dwarfs. The sum of the values for brown dwarfs T6 or cooler is 0.00455 per cubic parsec. For comparison the value for stars in the solar neighborhood is ~0.1 per cubic parsec.

Posted by: SolarSystemRubble Sep 27 2011, 06:00 AM

NASA To Host News Conference On Asteroid Search Findings WASHINGTON -- NASA will hold a news conference at 1 p.m. EDT on Thurs., Sept. 29, to reveal near-Earth asteroid findings and implications for future research. The briefing will take place in the NASA Headquarters James E. Webb Auditorium, located at 300 E St. SW in Washington.

NASA's Wide-field Infrared Survey Explorer (WISE) mission, launched in December 2009, captured millions of images of galaxies and objects in space. During the news conference, panelists will discuss results from an enhancement of WISE called Near-Earth Object WISE (NEOWISE) that hunted for asteroids.

The panelists are:
-- Lindley Johnson, NEO program executive, NASA Headquarters, Washington
-- Amy Mainzer, NEOWISE principal investigator, NASA's Jet Propulsion Laboratory, Pasadena, Calif.
-- Tim Spahr, director, Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, Mass.
-- Lucy McFadden, scientist, NASA's Goddard Space Flight Center, Greenbelt, Md.

The event will air live on NASA Television and the agency's website. For NASA TV streaming video, downlink and scheduling information, visit:

http://www.nasa.gov/ntv

The briefing also will be streamed live, with a chat available, at:

http://www.ustream.tv/nasajpl2

For more information about the mission, visit:


http://www.nasa.gov/wise


Posted by: Holder of the Two Leashes Aug 23 2013, 04:40 AM

WISE is going to be reactivated in September for a three year extended mission. It will only be to survey near earth objects, half of the infrared detectors don't work anymore (no coolant).

http://www.jpl.nasa.gov/news/news.php?release=2013-257

http://www.spaceflightnow.com/news/n1308/22wise/

Posted by: Holder of the Two Leashes Mar 11 2014, 06:35 PM

According to the latest analysis of WISE data from the prime survey, there are no close by objects the size of Saturn or larger, out to about 10,000 AU. That's a little less than two light months distance. And no Jupiters out to at least 26,000 AU, over a third of a light year.

http://wise.ssl.berkeley.edu/sciupdates_no_PlanetX.html

Posted by: Vultur Mar 14 2014, 01:43 AM

Ah... too bad. I was hoping "Tyche" would turn out to be real...

Posted by: antipode Apr 22 2014, 08:10 AM

Looks like K. Luhman has pulled yet another very close brown dwarf out of the WISE dataset.

At just over 2pc, 250k and under the Deuterium burning limit, this is our first ultra close free floating planet!

Abstract of discovery paper here:

http://iopscience.iop.org/2041-8205/786/2/L18

P

Posted by: Vultur Apr 23 2014, 01:33 AM

With that mass (3-10 Jupiter masses) and temperature, why is it called a "brown dwarf" at all? I thought that was above 13 Jupiter masses... is it because it didn't form in a protoplanetary disk?


Posted by: stevesliva Apr 26 2014, 12:40 AM

Press release here:
http://www.jpl.nasa.gov/news/news.php?release=2014-127

Warm Spitzer used to confirm. ("I'm not dead yet...")

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