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Kepler-20: A Sun-like Star with Three Sub-Neptune Exoplanets and Two Earth-size Candidates

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Complete Citation

  • Gautier, Thomas N., III, Charbonneau, David, Rowe, Jason F., Marcy, Geoffrey W., Isaacson, Howard, Torres, Guillermo, Fressin, Francois, Rogers, Leslie A., Désert, Jean-Michel, Buchhave, Lars A., Latham, David W., Quinn, Samuel N., Ciardi, David R., Fabrycky, Daniel C., Ford, Eric B., Gilliland, Ronald L., Walkowicz, Lucianne M., Bryson, Stephen T., Cochran, William D., Endl, Michael, Fischer, Debra A., Howell, Steve B., Horch, Elliott P., Barclay, Thomas, Batalha, Natalie et al. 2012. "Kepler-20: A Sun-like Star with Three Sub-Neptune Exoplanets and Two Earth-size Candidates." The Astrophysical Journal, 749 15. https://doi.org/10.1088/0004-637X/749/1/15.

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Abstract

  • We present the discovery of the Kepler-20 planetary system, which we initially identified through the detection of five distinct periodic transit signals in the Kepler light curve of the host star 2MASS J19104752 4220194. From high-resolution spectroscopy of the star, we find a stellar effective temperature T eff = 5455 ± 100 K, a metallicity of [Fe/H] = 0.01 ± 0.04, and a surface gravity of log g = 4.4 ± 0.1. We combine these estimates with an estimate of the stellar density derived from the transit light curves to deduce a stellar mass of M sstarf = 0.912 ± 0.034 M &sun; and a stellar radius of R sstarf = 0.944 0.060 -0.095 R &sun;. For three of the transit signals, we demonstrate that our results strongly disfavor the possibility that these result from astrophysical false positives. We accomplish this by first identifying the subset of stellar blends that reproduce the precise shape of the light curve and then using the constraints on the presence of additional stars from high angular resolution imaging, photometric colors, and the absence of a secondary component in our spectroscopic observations. We conclude that the planetary scenario is more likely than that of an astrophysical false positive by a factor of 2 × 105 (Kepler-20b), 1

Publication Date

  • 2012

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