Kepler News and Results (Thread 2)

http://arxiv.org/abs/1501.01101

VALIDATION OF TWELVE SMALL KEPLER TRANSITING PLANETS IN THE HABITABLE ZONE

We present an investigation of twelve candidate transiting planets from Kepler with orbital periods ranging from 34 to 207 days, selected from initial indications that they are small and potentially in the habitable zone (HZ) of their parent stars. Few of these objects are known. The expected Doppler signals are too small to confirm them by demonstrating that their masses are in the planetary regime. Here we verify their planetary nature by validating them statistically using the BLENDER technique, which simulates large numbers of false positives and compares the resulting light curves with the Kepler photometry. This analysis was supplemented with new follow-up observations (high-resolution optical and near-infrared spectroscopy, adaptive optics imaging, and speckle interferometry), as well as an analysis of the flux centroids. For eleven of them (KOI-0571.05, 1422.04, 1422.05, 2529.02, 3255.01, 3284.01, 4005.01, 4087.01, 4622.01, 4742.01, and 4745.01) we show that the likelihood they are true planets is far greater than that of a false positive, to a confidence level of 99.73% (3) or higher. For KOI-4427.01 the confidence level is about 99.2% (2.6). With our accurate characterization of the GKM host stars, the derived planetary radii range from 1.1 to 2.7R⊕. All twelve objects are confirmed to be in the HZ, and nine are small enough to be rocky. Excluding three of them that have been previously validated by others, our study doubles the number of known rocky planets in the HZ. KOI-3284.01 and KOI-4742.01 are the planets most similar to the Earth discovered to date when considering their size and incident flux jointly.

Eight of those are the batch announced yesterday (Kepler-436 to 443)
Three are previously-known systems Kepler-186, Kepler-296 (2 planets)
To my knowledge, KOI-4427 is a new one.

Oddly, (but then again, perhaps not,) the Habitable Exoplanet Catalog has Kepler-438b has being more habitable than Kepler-442b. If it isn't a runaway greenhouse, it's got to be pretty toasty!

-M-

The HPL tends to be rather dismal at evaluating the comparative habitability of planets.

http://arxiv.org/abs/1501.01305

KEPLER-445, KEPLER-446 AND THE OCCURRENCE OF COMPACT MULTIPLES ORBITING MID-M DWARF STARS

We confirm and characterize the exoplanetary systems Kepler-445 and Kepler-446: two mid-M dwarf stars, each with multiple, small, short-period transiting planets. Kepler-445 is a metal-rich ([Fe/H]=+0.25 ± 0.10) M4 dwarf with three transiting planets, and Kepler-446 is a metal-poor ([Fe/H]=-0.30 ± 0.10) M4 dwarf also with three transiting planets. Kepler-445c is similar to GJ 1214b: both in planetary radius and the properties of the host star. The Kepler-446 system is similar to the Kepler-42 system: both are metal-poor with large galactic space velocities and three short-period, likely-rocky transiting planets that were initially assigned erroneously large planet-to-star radius ratios. We independently determined stellar parameters from spectroscopy and searched for and fitted the transit light curves for the planets, imposing a strict prior on stellar density in order to remove correlations between the fitted impact parameter and planet-to-star radius ratio for short-duration transits. Combining Kepler-445, Kepler-446 and Kepler-42, and isolating all mid-M dwarf stars observed by Kepler with the precision necessary to detect similar systems, we calculate that 21 +7 −5 % of mid-M dwarf stars host compact multiples (multiple planets with periods of less than 10 days) for a wide range of metallicities. We suggest that the inferred planet masses for these systems support highly efficient accretion of protoplanetary disk metals by mid-M dwarf protoplanets.

http://arxiv.org/abs/1501.01486

SOPHIE velocimetry of Kepler transit candidates.
XV. KOI-614b, KOI-206b, and KOI-680b: a massive warm Jupiter orbiting a G0 metallic dwarf and two highly inflated planets with a distant companion around evolved F-type stars


We report the validation and characterization of three new transiting exoplanets using SOPHIE radial velocities: KOI-614b, KOI-206b, and KOI-680b. KOI-614b has a mass of 2.86±0.35 MJup and a radius of 1.13+0.26−0.18 RJup, and it orbits a G0, metallic ([Fe/H]=0.35±0.15) dwarf in 12.9 days. Its mass and radius are familiar and compatible with standard planetary evolution models, so it is one of the few known transiting planets in this mass range to have an orbital period over ten days. With an equilibrium temperature of Teq=1000±45 K, this places KOI-614b at the transition between what is usually referred to as "hot" and "warm" Jupiters. KOI-206b has a mass of 2.82±0.52 MJup and a radius of 1.45±0.16 RJup, and it orbits a slightly evolved F7-type star in a 5.3-day orbit. It is a massive inflated hot Jupiter that is particularly challenging for planetary models because it requires unusually large amounts of additional dissipated energy in the planet. On the other hand, KOI-680b has a much lower mass of 0.84±0.15 MJup and requires less extra-dissipation to explain its uncommonly large radius of 1.99±0.18 RJup. It is one of the biggest transiting planets characterized so far, and it orbits a subgiant F9-star well on its way to the red giant stage, with an orbital period of 8.6 days. With host stars of masses of 1.46±0.17 M⊙ and 1.54±0.09 M⊙, respectively, KOI-206b, and KOI-680b are interesting objects for theories of formation and survival of short-period planets around stars more massive than the Sun. For those two targets, we also find signs of a possible distant additional companion in the system.

KOI-0571=Kepler-186
KOI-1422=Kepler-296
KOI-2529.02=Kepler-436 b
KOI-3255.01=Kepler-437 b
KOI-3284.01=Kepler-438 b
KOI-4005.01=Kepler-439 b
KOI-4087.01=Kepler-440 b
KOI-4622.01=Kepler-441 b
KOI-4742.01=Kepler-442 b
KOI-4745.01=Kepler-443 b
KOI-4427.01=?
Edit: oups, it was already in the paper...

The two complex systems around mid-M dwarfs are good to see. Their figure 6 gives a fascinating comparison of scales in the systems.

Quote :

The planet-metallicity correlation, wherein higher metallicity stars are more likely to host gaseous planets, has been shown to be true for sun-like stars as well as early M dwarf stars. However, it has not been thoroughly investigated for mid-M dwarf stars due to the challenges in finding planets around them. It is therefore intriguing that Kepler-445 ([Fe/H]=+0.27±0.13) and GJ 1214 ([Fe/H]=+0.20) are the only mid-M dwarf starswith transiting planets larger than 2R_⊕… Based on this alone, we speculate that the planet-metallicity correlation may in fact extend down to mid-M dwarf stars for large planets (>2R_⊕).

Though such a position suffers from severe statistical limitations at the current juncture, it is fairly plausible that larger planets are easier to form around metal-rich stars for such low mass hosts and disks. This will probably become meaningfully testable in the near future.

Stalker wrote:

KOI-0571=Kepler-186
KOI-1422=Kepler-296
KOI-2529.02=Kepler-436 b
KOI-3255.01=Kepler-437 b
KOI-3284.01=Kepler-438 b
KOI-4005.01=Kepler-439 b
KOI-4087.01=Kepler-440 b
KOI-4622.01=Kepler-441 b
KOI-4742.01=Kepler-442 b
KOI-4745.01=Kepler-443 b
KOI-4427.01=?
Edit: oups, it was already in the paper...

EPE is listing Kepler-444 b:

http://exoplanet.eu/catalog/kepler-444_b/

Checking the discovery paper it has to be a typo since orbital parameters are those of Kepler-441 b, whereas the latter has those of KOI-4427.01 reported, the alleged (not announced yet) Kepler-444 b.

Interesting.

Just for the archive:
KOI-2704=Kepler-445
KOI-2842=Kepler-446

Presumably those will get added to the Kepler Names Table in the near future...

Regarding the batch of 8 habitable zone planets, it is worth a read of Andrew LePage's post Habitable Planet Reality Check: 8 New Habitable Zone Planets on his blog Drew Ex Machina. (It's definitely worth a look through the rest of the Habitable Planet Reality Check series in particular and the rest of the blog in general.)

More from Andrew LePage, this time regarding the candidates KOI-2194.03 and KOI-5737.01 (see the diagram in Led_Zep's post), which orbit sunlike stars: these seem to be promising as habitable planet candidates but need further work to verify their existence and pin down their properties.

Probability of being rocky for kepler 438 b is less than 70% it is weird should be at least 90%

Also it's good to point out than KOI 2194 = Kepler-371 which have 2 validate planets and now candidate in HZ KOI-2194.03 that wait to be confirm/validate.

I don't know if anyone post this paper here, so in any case I will post it.

http://arxiv.org/abs/1501.01623

The Occurrence of Potentially Habitable Planets Orbiting M Dwarfs Estimated from the Full Kepler Dataset and an Empirical Measurement of the Detection Sensitivity

We present an improved estimate of the occurrence rate of small planets around small stars by searching the full four-year Kepler data set for transiting planets using our own planet detection pipeline and conducting transit injection and recovery simulations to empirically measure the search completeness of our pipeline. We identified 157 planet candidates, including 2 objects that were not previously identified as Kepler Objects of Interest (KOIs). We inspected all publicly available follow-up images, observing notes, and centroid analyses, and corrected for the likelihood of false positives. We evaluate the sensitivity of our detection pipeline on a star-by-star basis by injecting 2000 transit signals in the light curve of each target star. For periods shorter than 50 days, we found an occurrence rate of 0.57 (+0.06/-0.05) Earth-size planets (1-1.5 Earth radii) and 0.51 (+0.07/-0.06) super-Earths (1.5-2 Earth radii) per M dwarf. Within a conservatively defined habitable zone based on the moist greenhouse inner limit and maximum greenhouse outer limit, we estimate an occurrence rate of 0.18 (+0.18/-0.07) Earth-size planets and 0.11 (+0.10/-0.05) super-Earths per M dwarf habitable zone. Accounting for the cooling effect of clouds by doubling the insolation limit at the inner edge of the habitable zone results in a higher occurrence rate of 0.27 (+0.16/-0.09) Earth-size planets and 0.25 (+0.11/- 0.07) super-Earths per M dwarf habitable zone.

Bonomo et al. "Improved parameters of seven Kepler giant companions characterized with SOPHIE and HARPS-N"
http://arxiv.org/abs/1501.02653

Kepler-39b, 41b, 43b, 44b, 74b, 75b and KOI-205b.

http://aas.org/media-press/archived-aas-press-conference-webcasts

Archived AAS Press Conference Webcasts
Press Conferences from AAS 225, Seattle, Washington, 4-8 January 2015

http://arxiv.org/abs/1501.03586

Detection of Potential Transit Signals in 17 Quarters of Kepler Mission Data

We present the results of a search for potential transit signals in the full 17-quarter data set collected during Kepler's primary mission that ended on May 11, 2013, due to the on-board failure of a second reaction wheel needed to maintain high precision, fixed, pointing. The search includes a total of 198,646 targets, of which 112,001 were observed in every quarter and 86,645 were observed in a subset of the 17 quarters. We find a total of 12,669 targets that contain at least one signal that meets our detection criteria: periodicity of the signal, a minimum of three transit events, an acceptable signal-to-noise ratio, and four consistency tests that suppress false positives. Each target containing at least one transit-like pulse sequence is searched repeatedly for other signals that meet the detection criteria, indicating a multiple planet system. This multiple planet search adds an additional 7,698 transit-like signatures for a total of 20,367. Comparison of this set of detected signals with a set of known and vetted transiting planet signatures in the Kepler field of view shows that the recovery rate of the search is 90.3%. We review ensemble properties of the detected signals and present various metrics useful in validating these potential planetary signals. We highlight previously undetected planetary candidates, including several small potential planets in the habitable zone of their host stars.


Page 3 :
As a result, the analysis reported here is the first which incorporates the full volume of data acquired from that field of view

http://exoplanetarchive.ipac.caltech.edu/index.html

January 15, 2015: Nine more confirmed Kepler planets have a home in the archive. See data on Kepler-433 b, Kepler-434 b, Kepler-435 b, Kepler-445 b, Kepler-445 c, Kepler-445 d, Kepler-446 b, Kepler-446 c, and Kepler-446 d in the Confirmed Planets table.


Kepler-433b = KOI-206.01
Kepler-434b = KOI-614.01
Kepler-435b = KOI-680.01

http://arxiv.org/abs/1501.01486

From previous post (Detection of Potential Transit Signals in 17 Quarters of Kepler Mission Data), some very interesting new candidates :

The first of these new candidates is on KIC target 8311864 and is the subject of a discovery paper already in the works that will be submitted for publication soon (Jenkins et al. 2015). The object has an orbital period of 384.85 days, a planet radius of 1.19 Re, and an equilibrium temperature of 221 K. Note that the stellar parameters for this system obtained through follow up spectroscopy are markedly different from those available to the SOC (Huber et al. 2014) for this run : the star is likely to be 1.2 Rs, providing a planet with a radius of 1.8 Re.

KIC target 5094751. This candidate has an orbital period of 362.5 days, a planet radius of 1.6 Re, and an equilibrium temperature of 301 K. This is KOI 123 (Kepler-109) which already has 2 confirmed planets.

KIC target 5531953. This candidate has an orbital period of 21.91 days, a planet radius of 0.78 Re, and an equilibrium temperature of 288 K. This is KOI 1681 which already has 3 dispositioned planet candidates.

KIC target 8120820. This candidate has an orbital period of 129.22 days, a planet radius of 1.84 Re, and an equilibrium temperature of 290 K.

KIC target 9674320. This candidate has an orbital period of 317.05 days, a planet radius of 1.66 Re, and an equilibrium temperature of 222 K.

KIC target 7100673. This candidate has an orbital period of 7.24 days, a planet radius of 0.77 Re, and an equilibrium temperature of 948 K. This is KOI 4032 which already has 4 dispositioned planet candidates, all with periods shorter than this one.

KIC target 8105398. This candidate has an orbital period of 224.15 days, a planet radius of 1.71 Re, and an equilibrium temperature of 292 K. This is KOI 5475.01

KIC target 8105398. This candidate has an orbital period of 5.68 days, a
planet radius of 0.55 Re, and an equilibrium temperature of 994 K. This is the second TCE detected on KOI 5475

TCE?

Oui mais comme c'est indiqué, KIC 8311864 a déjà un papier en préparation

On ne te voit plus sur Webastro ?

J'ai pas compris ce que veut dire TCE (et on ne parle pas français ici!)

Et oui il faut que je revienne sur WA un de ces 4

TCE = Threshold Crossing Event (read page 4)