Title: Kepler-62: A five-planet system with planets of 1.4 and 1.6 Earth radii in the Habitable Zone Authors: W. J. Borucki (1), E. Agol (12), F. Fressin (10), L. Kaltenegger (10 and 39), J. Rowe (6), H. Isaacson (2), D. Fischer (19), N. Batalha (1), J. J. Lissauer (1), G. W. Marcy (2), D. Fabrycky (17 and 42), J.-M. Désert (10), S. T. Bryson (1), T. Barclay (35), F. Bastien (43), A. Boss (4), E. Brugamyer (8), L. A. Buchhave (40 and 41), Chris Burke (6), D. A. Caldwell (6), J. Carter (18), D. Charbonneau (10), J. R. Crepp (20 and 38), J. Christensen-Dalsgaard (7), J. L. Christiansen (6), D. Ciardi (22), W. D. Cochran (8), E. DeVore (6), L. Doyle (6), A. K. Dupree (10), M. Endl (8), M. E. Everett (14), E. B. Ford (16), J. Fortney (17), T. N. Gautier III (11), J. C. Geary (10), A. Gould (13), M. Haas (1), C. Henze (1), A. W. Howard (24), S. B. Howell (1), D. Huber (32), J. M. Jenkins (6), H. Kjeldsen (7), et al. (21 additional authors not shown)
We present the detection of five planets -- Kepler-62b, c, d, e, and f -- of size 1.31, 0.54, 1.95, 1.61 and 1.41 Earth radii, orbiting a K2V star at periods of 5.7, 12.4, 18.2, 122.4 and 267.3 days, respectively. The outermost planets (Kepler-62e & -62f) are super-Earth-size (1.25 < planet radius/earth radius < 2.0) planets in the habitable zone (HZ) of their host star, receiving 1.2 ± 0.2 and 0.41 ± 0.05 times the solar flux at Earth's orbit. Theoretical models of Kepler-62e and -62f for a stellar age of ~7 Gyr suggest that both planets could be solid: either with a rocky composition or composed of mostly solid water in their bulk.
Title: Water Planets in the Habitable Zone: Atmospheric Chemistry, Observable Features, and the case of Kepler-62e and -62f Authors: L. Kaltenegger, D. Sasselov, S. Rugheimer
Water planets in the habitable zone are expected to have distinct geophysics and geochemistry of their surfaces and atmospheres. We explore these properties motivated by two key questions: whether such planets could provide habitable conditions and whether they exhibit discernable spectral features that distinguish a water planet from a rocky Earth-like planet. We show that the recently discovered planets Kepler-62e and -62f are the first viable candidates for habitable zone water planet. We use these planets as test cases for discussing those differences in detail. We generate atmospheric spectral models and find that potentially habitable water planets show a distinctive spectral fingerprint in transit depending on their position in the habitable zone.
In our solar system, only one planet is blessed with an ocean: Earth. Our home world is a rare, blue jewel compared to the deserts of Mercury, Venus and Mars. But what if our Sun had not one but two habitable ocean worlds? Astronomers have found such a planetary system orbiting the star Kepler-62. This five-planet system has two worlds in the habitable zone - the distance from their star at which they receive enough light and warmth for liquid water to theoretically exist on their surfaces. Modelling by researchers at the Harvard-Smithsonian Centre for Astrophysics (CfA) suggests that both planets are water worlds, their surfaces completely covered by a global ocean with no land in sight. Read more
NASA's Kepler Discovers its Smallest 'Habitable Zone' Planets to Date
NASA's Kepler mission has discovered two new planetary systems that include three super-Earth-size planets in the "habitable zone," the range of distance from a star where the surface temperature of an orbiting planet might be suitable for liquid water. The Kepler-62 system has five planets; 62b, 62c, 62d, 62e and 62f. The Kepler-69 system has two planets; 69b and 69c. Kepler-62e, 62f and 69c are the super-Earth-sized planets. Read more
Star Kepler-69 is a sun-like star (G-type, 93% the size of the Sun, 80% as luminous, about 2,700 light-years from Earth). Planet Kepler-69c is 70% larger than Earth, the smallest yet found in the habitable zone of a sun-like star. It orbits in 242 days, resembling the orbit of Venus. Planet Kepler-69b is just over twice the size of Earth and, orbiting every 13 days, is toasty hot, not even close to the habitable zone. Read more
New Techniques Allow Discovery of Smallest Super-Earth Exoplanets
A University of Washington astronomer, funded by a National Science Foundation (NSF) Faculty Early Career Development (CAREER) award, has discovered perhaps the smallest super-earth planet in its host star habitable zone. Eric Agol, an associate professor of astronomy at the University of Washington in Seattle, has identified Kepler 62f, a small, probably rocky planet orbiting a sun-like star in the Lyra constellation. The planet is about 1.4 times the size of Earth, receives about half as much solar flux, or heat and radiation, as Earth and circles its star in 267.3 (Earth) days. Read more