A SUPER-EARTH-SIZED PLANET ORBITING IN OR NEAR THE HABITABLE ZONE AROUND A SUN-LIKE STAR

Abstract

We present the discovery of a super-Earth-sized planet in or near the habitable zone of a Sun-like star. The host is Kepler-69, a 13.7 mag G4V-type star. We detect two periodic sets of transit signals in the 3-year flux time series of Kepler-69, obtained with the Kepler spacecraft. Using the very high precision Kepler photometry, and follow-up observations, our confidence that these signals represent planetary transits is >99.3%. The inner planet, Kepler-69b, has a radius of $2.24^{+0.44}_{-0.29}$ R and orbits the host star every 13.7 days. The outer planet, Kepler-69c, is a super-Earth-sized object with a radius of $1.7^{+0.34}_{-0.23}$ R and an orbital period of 242.5 days. Assuming an Earth-like Bond albedo, Kepler-69c has an equilibrium temperature of 299 ± 19 K, which places the planet close to the habitable zone around the host star. This is the smallest planet found by Kepler to be orbiting in or near the habitable zone of a Sun-like star and represents an important step on the path to finding the first true Earth analog.

Authors: Thomas Barclay, Christopher J. Burke, Steve B. Howell, Jason F. Rowe, Daniel Huber, Howard Isaacson, Jon M. Jenkins, Rea Kolbl, Geoffrey W. Marcy, Elisa V. Quintana, Martin Still, Joseph D. Twicken, Stephen T. Bryson, William J. Borucki, Douglas A. Caldwell, David Ciardi, Bruce D. Clarke, Jessie L Christiansen, Jeffrey L. Coughlin, Debra A. Fischer, Jie Li, Michael R. Haas, Roger Hunter, Jack J. Lissauer, Fergal Mullally, Anima Sabale ,  Shawn E. Seader, Jeffrey C. Smith, Peter Tenenbaum, A. K. M. Kamal Uddin, and Susan E. Thompson

Source:
http://iopscience.iop.org/0004-637X/768/2/101

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