KEPLER-21b: A 1.6 REarth planet transiting the bright oscillating F subgiant star HD179070

The Astrophysical Journal (Impact Factor: 5.99). 02/2012; 746:123 (18pp). DOI: 10.1088/0004-637X/746/2/123
Source: arXiv


We present Kepler observations of the bright (V = 8.3), oscillating star HD 179070. The observations show transit-like events which reveal that the star is orbited every 2.8 days by a small, 1.6 R
Earth object. Seismic studies of HD 179070 using short cadence Kepler observations show that HD 179070 has a frequency-power spectrum consistent with solar-like oscillations that are acoustic p-modes. Asteroseismic analysis provides robust values for the mass and radius of HD 179070, 1.34 ± 0.06 M
☉ and 1.86 ± 0.04 R
☉, respectively, as well as yielding an age of 2.84 ± 0.34 Gyr for this F5 subgiant. Together with ground-based follow-up observations, analysis of the Kepler light curves and image data, and blend scenario models, we conservatively show at the >99.7% confidence level (3σ) that the transit event is caused by a 1.64 ± 0.04 R
Earth exoplanet in a 2.785755 ± 0.000032 day orbit. The exoplanet is only 0.04 AU away from the star and our spectroscopic observations provide an upper limit to its mass of ~10 M
Earth (2σ). HD 179070 is the brightest exoplanet host star yet discovered by Kepler.

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Available from: Mario J. P. F. G. Monteiro
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