Exoplanets & Exomoons

Twelve Small Kepler Transiting Planets in the Habitable Zone

By Keith Cowing
January 7, 2015
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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.

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 sigma) or higher.

For KOI-4427.01 the confidence level is about 99.2% (2.6 sigma). With our accurate characterization of the GKM host stars, the derived planetary radii range from 1.1 to 2.7 R_Earth.

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.

Validation of Twelve Small Kepler Transiting Planets in the Habitable Zone

Guillermo Torres, David M. Kipping, Francois Fressin, Douglas A. Caldwell, Joseph D. Twicken, Sarah Ballard, Natalie M. Batalha, Stephen T. Bryson, David R. Ciardi, Christopher E. Henze, Steve B. Howell, Howard T. Isaacson, Jon M. Jenkins, Philip S. Muirhead, Elisabeth R. Newton, Erik A. Petigura, Thomas Barclay, William J. Borucki, Justin R. Crepp, Mark E. Everett, Elliott P. Horch, Andrew W. Howard, Rea Kolbl, Geoffrey W. Marcy, Sean McCauliff, Elisa V. Quintana (Submitted on 6 Jan 2015)

Comments: 27 pages in emulateapj format, including tables and figures. To appear in The Astrophysical Journal

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

Cite as: arXiv:1501.01101 [astro-ph.EP] (or arXiv:1501.01101v1 [astro-ph.EP] for this version)

Submission history From: Douglas Caldwell [v1] Tue, 6 Jan 2015 07:36:42 GMT (2899kb) http://arxiv.org/abs/1501.01101

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻