Kepler News and Results

Kepler session will be streamed live, starting in three hours.

Only new information so far is that KOI-961 is now Kepler-42.

KOI-284 has most likely two stars, two planets orbiting one star and one another star.

Kepler-38 is presented, a new circumbinary planet orbiting two stars with a luminosity ratio of ~1,000. Planet is Neptune-sized.

Sirius_Alpha wrote:

Kepler-38 is presented, a new circumbinary planet orbiting two stars with a luminosity ratio of ~1,000. Planet is Neptune-sized.

Slightly evolved solar mass star + red dwarf.

jyril wrote:

Sirius_Alpha wrote:

Kepler-38 is presented, a new circumbinary planet orbiting two stars with a luminosity ratio of ~1,000. Planet is Neptune-sized.

Slightly evolved solar mass star + red dwarf.

Binaries like these are my least favorite (with some exceptions), which is why Kepler-16 was so disappointing when I looked it up. Out of all the circumbinaries discovered so far, -35 is my favorite. Hope to find more like -35, variations welcome.

Quote :

http://kepler.nasa.gov/

Kepler official website increases planet counter up to 72 Kepler planets.

Some results on the frequency of planets:

* Hot Jupiters are 1000x less common than Earth to Neptune-sized planets.
* There is a paucity of planets < 2R_Earth. This could be due to observational bias, or not.
* I didn't fully catch it, but apparently Kepler target stars have a planet of any size in the habitable zone at the frequency of ~0.1%.

In addition, according to Marcy, the transition between terrestrials and planets with a large number of volatiles is somewhere between 2-3 R_Earth.

Edasich wrote:

Quote :

http://kepler.nasa.gov/

Kepler official website increases planet counter up to 72 Kepler planets.

That's the number of planets on the list if you count community-based detections and exclude the three planets discovered before Kepler... Or perhaps it already includes the unpublished Kepler planets.

I see KOI-961 aka Kepler-42 has already been updated (and yes, it is a pun ).

"Kepler-38b mass is uncertain. Could be around 120 Earth-masses...or it could be closer to 20."
Radius: 0,385 Rj

Between 15-20 or even 10

jyril wrote:

* I didn't fully catch it, but apparently Kepler target stars have a planet of any size in the habitable zone at the frequency of ~0.1%.

Is that before or after correcting for the observational biases of the transit method I wonder?

Before, if I recall. ~0.1% of their target stars have transiting planet candidates of any size.

Couple of very interesting tweets...

Quote :

@govertschilling
thomas barclay: smallest exoplanet candidate yet is moon-sized, in 15d-period around sun-like star. that's small! #aas220

Quote :

@govertschilling
thomas barclay expects first detection of binary planet or planetary satellite or ring system within approx 18 months #aas220

And..

Quote :

Thomas Barclay: #Kepler has roughly a dozen planet candidates smaller than Mars. #aas220

Incredible dozen smaller than mars and moon size??wow

A moon-sized candidate around a sun-like star? How did they achieve that?
I could believe an M dwarf, but a sun-like star?

Indeed! Kepler was not supposed to find planets smaller than Mercury, and that prediction was before the higher level of chromospheric activity in sunlike stars was known...

How shallow is transit of moon size planet around g star?? maybe it is artifact or star spot?

If correct then PSR B1257+12A may finally get deposed from its status as the smallest known planet...

I am not sure about it,I doubt as pulsar smallest planet is mass known and in this case of kepler candidate only size

I guess only way to get the mass of the planet is to have a multi-planet system. If that system had more massive planets in close orbits, they could perturb the planet allowing a rough estimation of its mass. This one is probably way too small to produce detectable disturbations on other planets.

For the pulsar planets, only rough estimations could be given (ball of iron to ball of some light solid materials).

Kepler-36 b and c.
Two planets very close to each other, very different densities.
http://www.nasa.gov/mission_pages/kepler/news/planetary-odd-couple.html

The clue to the current state of the Kepler-36 system is in the star.

Taking data from the Kepler website, Kepler-36 has an effective temperature of 5911 K, 1.615 times the Sun's diameter, which would mean that the star has 2.85 times the luminosity of the Sun. Kepler-36 would be a subgiant with spectral type G0IV, meaning that the star has stopped burning hydrogen in its core and is now expanding on its way to becoming a true giant with a dead helium core.

Kepler-36's status as a subgiant can easily explain the differences between Kepler-36b and Kepler-36c. Very likely, both planets formed beyond the snow line as ice planets (think larger version of Jupiter's large moons). Both planets then migrated inwards to where they are now.

Kepler-36b, being the smaller of the two planets, lost all of its volatiles early on, leaving behind a rocky core. The volatiles would have been blown away while Kepler-36 was still a hydrogen fusing dwarf.

Kepler-36c, on the other hand, was able to hold onto its volatiles due to its larger mass. While Kepler-36 was still on the main sequence, the planet was able to hold onto its volatiles -- particularly water vapor, oxygen, and methane. The planet would have had a diameter roughly 2.2 to 2.4 times that of Earth. Once Kepler-36 gave up hydrogen fusion in its core, the star turned into a subgiant with its luminosity and size increasing over time. As Kepler-36's luminosity continued to climb, Kepler-36c continued to get hotter, reaching the point where the planet is no longer able to hold onto its volatiles. The result is that Kepler-36c is getting its volatiles boiled off at a very fast clip. The planet should look a lot like a giant comet up close.