title: An Earth-sized planet in the habitable zone of a cool star.
abstract: The quest for Earth-like planets is a major focus of current exoplanet research. Although 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 surfaces. 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 solar-radius star. The intensity and spectrum of the star's radiation place Kepler-186f in the stellar habitable zone, implying that if Kepler-186f has an Earth-like atmosphere and water at its surface, then some of this water is likely to be in liquid form.
authors.affiliation: SETI Institute, 189 Bernardo Avenue, Suite 100, Mountain View, CA 94043, USA.
authors.forename: Elisa V
authors.initials: EV
authors.lastname: Quintana
authors.forename: Thomas
authors.initials: T
authors.lastname: Barclay
authors.forename: Sean N
authors.initials: SN
authors.lastname: Raymond
authors.forename: Jason F
authors.initials: JF
authors.lastname: Rowe
authors.forename: Emeline
authors.initials: E
authors.lastname: Bolmont
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Caldwell
authors.forename: Steve B
authors.initials: SB
authors.lastname: Howell
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Kane
authors.forename: Daniel
authors.initials: D
authors.lastname: Huber
authors.forename: Justin R
authors.initials: JR
authors.lastname: Crepp
authors.forename: Jack J
authors.initials: JJ
authors.lastname: Lissauer
authors.forename: David R
authors.initials: DR
authors.lastname: Ciardi
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Coughlin
authors.forename: Mark E
authors.initials: ME
authors.lastname: Everett
authors.forename: Christopher E
authors.initials: CE
authors.lastname: Henze
authors.forename: Elliott
authors.initials: E
authors.lastname: Horch
authors.forename: Howard
authors.initials: H
authors.lastname: Isaacson
authors.forename: Eric B
authors.initials: EB
authors.lastname: Ford
authors.forename: Fred C
authors.initials: FC
authors.lastname: Adams
authors.forename: Martin
authors.initials: M
authors.lastname: Still
authors.forename: Roger C
authors.initials: RC
authors.lastname: Hunter
authors.forename: Billy
authors.initials: B
authors.lastname: Quarles
authors.forename: Franck
authors.initials: F
authors.lastname: Selsis
mesh_terms: D018534:Earth, Planet; D018559:Exobiology; D005118:Extraterrestrial Environment; D016083:Planets; D055609:Stars, Celestial; D014867:Water
chemical_list: D014867:Water