Kepler Mission Options

[JRehling]

Here's my analysis of possible earthlike planets in Kepler results:

http://sciencepiazza.blogspot.com/2014/04/...her-earths.html

The main finding is that we can't point to any particular Kepler discovery and deem it certain to be earthlike, but there are six top candidates which stand a good chance of including one or two that will prove to be pretty earthlike.

[Explorer1]

Telecon tomorrow on a new Kepler discovery (embargoed until 11:00 PST):

http://www.jpl.nasa.gov/news/news.php?release=2014-113

[0101Morpheus]

This is fairly sudden. Normally they do not announce teleconferences this early in advance.

They might be ready to unveil an interesting planetary system like Kepler 62.

[JRehling]

The people speaking and their research areas seem to draw a bullseye around the topic of terrestrial planets with earthlike temperatures, which happened to be the topic of my last blog post:

http://sciencepiazza.blogspot.com/2014/04/...her-earths.html

I guess they're either going to be talking about a new candidate for most-earthlike-exoplanet-yet, or a significant advance in the quality of information about a Kepler discovery that was already on the books.

EDIT: You may want to pay close attention to the seventh Kepler candidate in the table of my post, K00571.05.

[DEChengst]

Dutch news sites are breaking the embargo:

http://nos.nl/artikel/637138-planeet-zoals...e-gevonden.html

Kepler-186f
Rocky and 10% > Earth
In the "Goldilocks zone"
Orbits a red dwarf once every 130 days
Distance of 500 light years

[Explorer1]

Yep:

http://www.nasa.gov/ames/kepler/nasas-kepl...f-another-star/

No surprise that its a red dwarf...

[JRehling]

The press conference has just begun. Since the embargo is over, I'll link to the post I wrote in preparation, giving my take on the findings:

http://sciencepiazza.blogspot.com/2014/04/...ther-earth.html

The planet in question was seventh on my list of possible "other Earths" in the previous post:

http://sciencepiazza.blogspot.com/2014/04/...her-earths.html

The advantage this one has over many of the other candidates is that it's in a multiple-discovery system, which makes it easier to validate the existence of the candidates.

Note that while the star is a red dwarf, the planet's orbital period is relatively long (130 days), longer than Mercury's, so concerns about tidal lock may not apply in this case.

[0101Morpheus]

I suppose that more habitable candidates will be confirmed in the future. If we judge that the smaller stars will be confirmed first, then we have an order of discovery of M, K, then G stars. My question is as the team confirms more candidates, will the Kepler team be releasing more rapid announcements like this one or withhold them for releasing later in a Kepler science conference? I can see the upsides and downsides of both and I don't know which is more likely.

[TheAnt]

Note that while the star is a red dwarf, the planet's orbital period is relatively long (130 days), longer than Mercury's, so concerns about tidal lock may not apply in this case.

"May not apply" is a good reservation there. =)
The orbital period is longer since the planet move in the weaker gravitational field of a red dwarf.
So it is relatively close to the star, even though it appear to be one of the brighter ones of the class.
Lets wait and see, a lot of instruments will quite likely be aimed at this system in years to come so more facts will trickle down.
The interest for a planet of this kind will be enormous.
None the least because it fits with a hypothesis that Earth type planets could indeed exist orbiting red dwarfs.

And thank you for your blog, I will link it to some people who are interested in more information. =)

[JRehling]

[[If we judge that the smaller stars will be confirmed first, then we have an order of discovery of M, K, then G stars.]]

My estimate was that there should be about one of these around an M and about one around a G in the Kepler data. Intrinsically, there should be far more earthlike planets around Ms than Ks or Gs, but Kepler was observing far more Gs (~90,000) than Ms (~4,000).

[["May not apply" is a good reservation there.]]

The specifics of tidal interactions depend upon internal structural factors that we don't even know in the case of Mars, much less an exoplanet.

This one seems very promising not to be tidally locked, but it could go either way. For many smaller red dwarfs, the orbital period of any earthlike planets would be much shorter and almost certainly result in tidally locked rotation.

[[And thank you for your blog, I will link it to some people who are interested in more information.]]

That would be great! I hope it's useful to people.

[Mongo]

This one seems very promising not to be tidally locked, but it could go either way. For many smaller red dwarfs, the orbital period of any earthlike planets would be much shorter and almost certainly result in tidally locked rotation.

Formation, tidal evolution and habitability of the Kepler-186 system

Given that the system is probably older than a few Gyr, simulations of tidal evolution show that the four inner planets of the system are in pseudo-synchronous rotation (respectively, Prot = ~4, ~7, ~13, ~22 and ~130 days) with very low obliquities (< 1 degree). However, in a few simulations the obliquity of Kepler-186d was excited to more than 10 degrees due to a brief but deep crossing of the 5:3 mean motion resonance between Kepler-186c and Kepler-186d. The competition between the excitation due to planet-planet gravitational interactions and tidal damping has the effect of stabilizing this relatively high obliquity on ~10 Myr timescales.

We also showed that given the uncertainties on the age of the star as well as the uncertainties on the composition and tidal dissipation, the rotation state of Kepler-186f is unconstrained. If the system is somewhat younger (1 Gyr old) or if the tidal dissipation of Kepler-186f is lower than that of Earth's, Kepler-186f could still be in the process of pseudo-synchronization and its obliquity could be high. However, if the system is about 4 Gyr old or the tidal dissipation of Kepler-186f is Earth-like, Kepler-186f would be pseudo-synchronized with a long rotation period (~130 days). The variety of spin states of Kepler-186f should then be investigated by exoplanet-climate modelers.

[Mongo]

Paper is now up on arXiv:

An Earth-sized Planet in the Habitable Zone of a Cool Star

The quest for Earth-like planets represents a major focus of current exoplanet research. While planets that are Earth-sized and smaller have been detected, these planets reside in orbits that are too close to their host star to allow liquid water on their surface. We present the detection of Kepler-186f, a 1.11+\-0.14 Earth radius planet that is the outermost of five planets - all roughly Earth-sized - that transit a 0.47+\-0.05 Rsun star. The intensity and spectrum of the star's radiation places Kepler-186f in the stellar habitable zone, implying that if Kepler-186f has an Earth-like atmosphere and H2O at its surface, then some of this H2O is likely to be in liquid form.

[nprev]

MOD NOTE: Exoplanet designation posts moved here.

[dtolman]

K2 is approved, and the first 75 day observation campaign begins May 30th.
I hope those remaining two reaction wheels can last for many campaigns to come...

[0101Morpheus]

This is great news.

If K2 can get a single year of observations, I'd consider it a success many times over.