Masses, Radii, and Orbits of Small Kepler Planets: The Transition from Gaseous to Rocky Planets

G. W. Marcy, H. Isaacson, A. W. Howard, J. F. Rowe, J. M. Jenkins, S. T. Bryson, D. W. Latham, S. B. Howell, T. N. Gautier III, N. Batalha, L. Rogers, D. Ciardi, D. A. Fischer, R. L. Gilliland, H. Kjeldsen, J. Christensen-Dalsgaard, D. Huber, W. J. Chaplin, S. Basu, L. A. Buchhave, S. N. Quinn, W. J. Borucki, D. Koch, R. Hunter, D. A. Caldwell, J. Van Cleve, R. Kolbl, L. M. Weiss, E. Petigura, S. Seager, T. Morton, J. Asher Johnson, S. Ballard, C. Burke, W. D. Cochran, M. Endl, P. J. MacQueen, M. Everett, J. J. Lissauer, E. B. Ford, G. Torres, F. Fressin, T. M. Brown, J. H. Steffen, D. Charbonneau, G. S. Basri, D. Sasselov, J. N. Winn, R. Sanchis-Ojeda, J. L. Christiansen, E. Adams, C. E. Henze, A. Dupree, D. C. Fabrycky, J. J. Fortney, J. Tarter, M. J. Holman, P. Tenenbaum, A. Shporer, P. W. Lucas, W. F. Welsh, J. A. Orosz, T. R. Bedding, T. L. Campante, G. R. Davies, Y. Elsworth, R. Handberg, S. Hekker, C. Karoff, S. D. Kawaler, M. N. Lund, M. Lundkvist, T. S. Metcalfe, A. Miglio, V. Silva Aguirre, D. Stello, T. R. White, A. Boss, R.-J. Dettmar, A. Gould, A. Prša, E. Agol, T. Barclay, J. Coughlin, E. Brugamyer, F. Mullally, E. V. Quintana, M. Still, S. E. Thompson, D. Morrisson, J. D. Twicken, J.-M. Désert, J. Carter, J. R. Crepp, G. Hébrard, A. Santerne, C. Moutou, C. Sobeck, D. Hudgins, M. R. Haas, P. Robertson, J. Lillo Box, D. Barrado-Navascues

Abstract
We report on the masses, sizes, and orbits of the planets orbiting 22 Kepler stars. There are 49 planet candidates around these stars, including 42 detected through transits and 7 revealed by precise Doppler measurements of the host stars. Based on an analysis of the Kepler brightness measurements, along with high-resolution imaging and spectroscopy, Doppler spectroscopy, and (for 11 stars) asteroseismology, we establish low false-positive probabilities (FPPs) for all of the transiting planets (41 of 42 have an FPP under 1%), and we constrain their sizes and masses. Most of the transiting planets are smaller than three times the size of Earth. For 16 planets, the Doppler signal was securely detected, providing a direct measurement of the planet's mass. For the other 26 planets we provide either marginal mass measurements or upper limits to their masses and densities; in many cases we can rule out a rocky composition. We identify six planets with densities above 5 g cm^–3, suggesting a mostly rocky interior for them. Indeed, the only planets that are compatible with a purely rocky composition are smaller than ~2 R _⊕. Larger planets evidently contain a larger fraction of low-density material (H, He, and H₂O).

Keywords
planetary systems - planets and satellites: detection - stars: individual: Kepler-25 Kepler-37 Kepler-48 Kepler-68 Kepler-93 Kepler-94 Kepler-95 Kepler-96 Kepler-97 Kepler-98 Kepler-99 Kepler-100 Kepler-102 Kepler-103 Kepler-106 Kepler-109 Kepler-113 Kepl

The Astrophysical Journal Supplement Series
Volume 210, Page 20_1
February 2014

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