Darin, Thanks for the comment. By the way, you...

2011-12-13T20:41:36.531-08:00

Darin,

Thanks for the comment. By the way, you really need to "leak" some great rumor from Kepler as a test to follow how internet rumors spread. Let me suggest some of the following tactics:

1. Write a fake letter in the Nature style with a title and abstract stating an earthsize planet in a habitable zone with a rocky surface a similar atmpophere has been found and print it at a printer accessible to many people at the CFA and just leave it there a couple days and see what happens.

2. Then make some anonymous comments on key places on the internet swearing the same thing.

3. Okay I give up, but it would be great to see how to start a great rumor and track how it builds once started.

Yes, in all likelihood, Kepler-22b is a "warm...

2011-12-13T18:00:59.601-08:00

Yes, in all likelihood, Kepler-22b is a "warm Neptune" with a thick gaseous atmosphere and no solid surface. It's important to note that the moniker "super-Earth" is just a code name for the rough size and does not imply that we have any information on the planet's composition. I actually kinda liked how the NASA graphics sort of suggested this by making the picture look somewhat enigmatic (can't tell if its all atmosphere or if there's a continent down there).

The popularity of this story just goes to show you what the words "habitable zone" will do... we've discovered gas giants in the habitable zone before (which probably got their fanfare at the time) and given that Kepler-22b is certainly smaller, though probably not qualitatively different, means that it's actually not that new of a discovery in some sense. As Nick pointed out, though, Kepler will surely deliver more and more interesting planets along these lines. The "candidates" are generally 80-90% true planets, so its practically certain that we've got plenty of nice small temperate worlds out there.

You mentioned measuring the mass with the radial velocity (Doppler wobble) technique, which would indeed be great. However, it's not plausible for the vast majority of Kepler targets: Kepler's goal was to get a good estimate of the frequency by detecting large numbers of worlds in a small patch of sky, which requires observing around stars that are too faint for radial velocity (and Hubble and Spitzer can't say anything about the atmospheres either). The opposite extreme, covering the whole sky to finding the brightest, most interesting targets is the goal of the proposed TESS mission.

It turns out, the best way to measure the mass of faint Kepler planets is through a different technique where you detect the gravitational influence between planets in a multiple planet system (as most exoplanetary systems are). These is known as transit timing variations. These are often weak and sometimes only an upper limit mass is derivable, but the nice thing is that all you need is Kepler data and patience (as it can take years for the signals to evolve to the point where a unique mass measurement is possible). We also need NASA to decide to fund Kepler through an extended mission, which is actually going to be a harder sell than you might imagine since the budget is so tight.

Anyway, I'm on the Kepler group working on these and we're excited about the possibilities, though frankly a true Earth twin (habitable zone 1 Earth mass planet around a Sun-like star) is most likely out of reach. However, we'll measure masses for several (maybe dozens) of planets in the small Earth-like size regime and perhaps from that and from what we learn about planet formation we'll be able to reasonably extrapolate to some of these habitable-zone Earth candidates.

Anyway, feel free to contact me (e-mail in my CV) if you have any Kepler questions. Also keep your eyes open for more Kepler announcements at the Texas AAS meeting in a few weeks...

Darin Ragozzine

PS I'm a satisfied lurker on theeternaluniverse and hope you all keep up the good work!

This is really cool stuff. I hope to see a day wh...

2011-12-05T16:18:04.890-08:00

This is really cool stuff. I hope to see a day where we discover life on another planet. :)

Comments on The Eternal Universe: Kepler Finds A Possibly Live One

Darin, Thanks for the comment. By the way, you...

Yes, in all likelihood, Kepler-22b is a "warm...

This is really cool stuff. I hope to see a day wh...