Kepler-18b, c, and d: A System of Three Planets Confirmed by Transit Timing Variations, Light Curve Validation, Warm-Spitzer Photometry, and Radial Velocity Measurements
We report the detection of three transiting planets around a Sun-like star, which we designate Kepler-18. The transit signals were detected in photometric data from the Kepler satellite, and were confirmed to arise from planets using a combination of large transit-timing variations (TTVs), radial ve...
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Veröffentlicht in: | The Astrophysical journal. Supplement series 2011-11, Vol.197 (1), p.7-jQuery1323919489348='48' |
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Sprache: | eng |
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Zusammenfassung: | We report the detection of three transiting planets around a Sun-like star, which we designate Kepler-18. The transit signals were detected in photometric data from the Kepler satellite, and were confirmed to arise from planets using a combination of large transit-timing variations (TTVs), radial velocity variations, Warm-Spitzer observations, and statistical analysis of false-positive probabilities. The Kepler-18 star has a mass of 0.97 M , a radius of 1.1 R , an effective temperature of 5345 K, and an iron abundance of [Fe/H] = +0.19. The planets have orbital periods of approximately 3.5, 7.6, and 14.9 days. The innermost planet 'b' is a 'super-Earth' with a mass of 6.9 ? 3.4 M {circled plus}, a radius of 2.00 ? 0.10 R {circled plus}, and a mean density of 4.9 ? 2.4 g cm3. The two outer planets 'c' and 'd' are both low-density Neptune-mass planets. Kepler-18c has a mass of 17.3 ? 1.9 M {circled plus}, a radius of 5.49 ? 0.26 R {circled plus}, and a mean density of 0.59 ? 0.07 g cm3, while Kepler-18d has a mass of 16.4 ? 1.4 M {circled plus}, a radius of 6.98 ? 0.33 R {circled plus} and a mean density of 0.27 ? 0.03 g cm3. Kepler-18c and Kepler-18d have orbital periods near a 2:1 mean-motion resonance, leading to large and readily detected TTVs. |
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ISSN: | 0067-0049 1538-4365 |
DOI: | 10.1088/0067-0049/197/1/7 |