Kepler Mission Options

[Habitable Zoner]

I asked an attendee at the APS conference if she had attended the Borucki talk on Kepler yesterday, and here was her reply: "I didn't see the talk myself, but from what I heard it was a summary of recent Kepler work - no new results." We'll try to be patient--certainly more at the AAS 216 meeting in Miami 23-27 May 2010, if not before.

[djellison]

Given that
- The exciting stuff is going to be earth like planets in Earth like orbits
- It takes three transits to confirm a planet discovery and then follow up obs from ground based scopes
- There is an epic quantity of data to get through

....people need to put the brakes on expectations of early results.

[Habitable Zoner]

Understood. But I personally would feel that the discovery of numerous hot super-earths would be monumental. And I am chomping at the bit to hear about earth-sized or smaller planets being detected, regardless of the orbit. That announcement could could certainly come during the first half of this year, perhaps at the May AAS meeting. And while earth-like planets in earth-like orbits are certainly the gold ring, it is conceivable that a (super)earth in a habitable zone around a dimmer star could be discovered by the end of 2010, a year and a half after Kepler's first light. For example, a planet circling a star with half the sun's mass could have a two-month orbit and still fall within that star's habitable zone. I'd say the odds of headline-grabbing results during the next three months and again within the next nine months are quite good.

[Hungry4info]

Do remember that most Kepler stars are inherently dim. Getting RV follow up to confirm a super-Earth is going to be tough. Recall how difficult it was to detect CoRoT-7 b. They sat on that for eons collecting data to announce a confirmation. If we get super-Earths around anything from Kepler by the end of 2010, I personally will be impressed.

But... I was impressed when the first batch contained a Neptune...

[Greg Hullender]

I think part of the idea is to get comfortable distinguishing planetary transits from other events, using RV measures as the gold standard. Then, when they find objects too small to double-check with RV, they'll be fairly confident of their results.

I'm just speculating here, but that's how I'd go about it. That being the case, I'll bet they've already got quite a number of possible Earth-sized planets with orbital periods of days or weeks around K-type stars. They just want to be sure.

--Greg

[Greg Hullender]

Another Mission Manager Update:

http://www.kepler.arc.nasa.gov/news/mmu/in...s&NewsID=34

No safe mode since 2/2, but they're still not sure of the cause. They're planning "mitigations" to reduce the impact, if another one happens.

I'm still worried about the possible MOD-3 failure reported in January:

http://www.kepler.arc.nasa.gov/news/mmu/in...s&NewsID=22

Hopefully no news is good news, but it'd have been nice if they'd mentioned it.

--Greg

[Habitable Zoner]

This statement also caught my eye: "The science team has just begun the follow-on observing season for 2010. At this time, the Kepler star field is visible for about one hour just before dawn. The Kepler star field will be visible for several months from the Earth’s northern hemisphere." Are they saying that they can only perform follow-on observations for a few months out of the year? Is observation from the southern hemisphere not possible?

[nprev]

I don't think that it is observable from the Southern Hemisphere (IIRC, it's in or near Cygnus in the northern sky). However, that has nothing to do with the fact that pretty much any non-circumpolar area of the sky is washed out by the Sun for at least a few months each year as the Earth orbits.

[Greg Hullender]

From Seattle (latitude 47 degrees 36 minutes 35 seconds north), Kepler's field of view (centered at declination +44 degrees 30 minutes) is circumpolar. Not that anyone would bother building a telescope here, but . . .

--Greg

[nprev]

True. I don't think that there are any large ground-based scopes (large enough to check Kepler observations, anyhow) far enough north to take advantage of that, though.

What is the most northerly truly large scope, anyhow? The 200-inch @ Palomar? The real titans all seem to be close to the Equator.

[Greg Hullender]

A better question would be how large a telescope is required to test Kepler's results. Lick is 120" and it's quite a bit north of Palomar.

--Greg

[Mongo]

True. I don't think that there are any large ground-based scopes (large enough to check Kepler observations, anyhow) far enough north to take advantage of that, though.

What is the most northerly truly large scope, anyhow? The 200-inch @ Palomar? The real titans all seem to be close to the Equator.

The most northerly telescopes by mirror diameter:

11.88m -- Large Binocular Telescope (Mt. Graham Obs.) -- 32.42N
5.08m -- Hale Telescope (Palomar Mountain Obs.) -- 33.21N
4.20m -- Large Sky Area Multi-Object Spectroscopic Telescope (Xinglong Station) -- 40.23N
2.64m -- Shajn (Crimean Astrophysical Obs.) -- 44.44N
2.00m -- Alfred Jensch Teleskop (Karl Schwartzschild Obs.) -- 50.58N

Also, there are the following more limited telescopes:

6.00m -- Bolshoi Teleskop Azimutalnyi (Nizhny Arkhyz) -- 43.39N -- very poor imagery due to large thermal mass, but still good for spectroscopic studies
2.65m -- UBC-Laval Liquid Mirror Telescope -- 49.28N -- obvious limitations due to its liquid mirror design

[Habitable Zoner]

What ground-based scopes actually are involved in checking Kepler observations? Is there a list somewhere?

[bluemars1]

What ground-based scopes actually are involved in checking Kepler observations? Is there a list somewhere?

Here is some info from a press release:

http://mcdonaldobservatory.org/news/releases/2010/0104.html

"Ground-based follow up is essential to Kepler’s planet-discovery process. ...using telescopes at a number of observatories on the ground to confirm or disprove they exist. Cochran’s team uses two telescopes at McDonald Observatory for this: the 9.2 meter Hobby-Eberly Telescope (one of the world’s largest) and the 2.7 meter Harlan J. Smith Telescope."

and

"Once a candidate star is identified, he said, it’s first observed by either the 2.7-meter Harlan J. Smith Telescope at McDonald Observatory or similar-size telescopes at other observatories. This step is done to determine what type of star it is — to eliminate any stars whose light simply mimics the signature of a transiting planet (such as an eclipsing binary star). The Harlan J. Smith Telescope has been used to vet 60 to 70 planet possibilities from Kepler, Cochran said."

and

"“We look at the ones that survive the recon work, and prioritize them. If a star is a good candidate for further study, it is passed on to a large telescope like the Hobby-Eberly Telescope (HET) at McDonald Observatory or the Keck 1 Telescope in Hawaii.”

[Mongo]

10.00m -- Keck 1 -- 19.50N
9.20m -- Hobby-Eberly Telescope -- 30.40N
2.72m -- Harlan J Smith Telescope -- 30.40N

Hobby-Eberly is fairly far north for its light-gathering abilities. Keck 1 is a bit far to the south, though. Other 8m class telescopes that are significantly further north than Keck 1 include the following:

11.88m -- Large Binocular Telescope -- 32.42N
10.40m -- Gran Telescopio Canarias -- 28.46N
6.50m -- MMT -- 31.41N

Obviously, obtaining time on any of these telescopes is the limiting factor, so beggars can't be choosers.