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.

Elisa V. Quintana, Thomas Barclay, Sean N. Raymond, Jason F. Rowe, Emeline Bolmont, Douglas A. Caldwell, Steve B. Howell, Stephen R. Kane, Daniel Huber, Justin R. Crepp, Jack J. Lissauer, David R. Ciardi, Jeffrey L. Coughlin, Mark E. Everett, Christopher E. Henze, Elliott Horch, Howard Isaacson, Eric B. Ford, Fred C. Adams, Martin Still, Roger C. Hunter, Billy Quarles, Franck Selsis (Submitted on 22 Apr 2014)

Comments: Main text and supplemental material combined. This is the author’s version of the work. It is posted here by permission of the AAAS for personal use, not for redistribution. The definitive version was published in Science on 18 April 2014, Vol. 344, #6181. Published version available from this http URL

Subjects: Earth and Planetary Astrophysics (astro-ph.EP) DOI: 10.1126/science.1249403 Cite as: arXiv:1404.5667 [astro-ph.EP) (or arXiv:1404.5667v1 [astro-ph.EP] for this version)

Submission history From: Thomas Barclay [v1] Tue, 22 Apr 2014 23:18:09 GMT (5323kb)