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arXiv · 1112.2165

Kepler-21b: A 1.6REarth Planet Transiting the Bright Oscillating F Subgiant Star HD 179070

Steve B. Howell·Jason F. Rowe·Stephen T. Bryson·Samuel N. Quinn·Geoffrey W. Marcy·Howard Isaacson·David R. Ciardi·William J. Chaplin·Travis S. Metcalfe·Mario J. P. F. G. Monteiro·Thierry Appourchaux·Sarbani Basu·Orlagh L. Creevey·Ronald L. Gilliland·Pierre-Olivier Quirion·Denis Stello·Hans Kjeldsen·Jorgen Christensen-Dalsgaard·Yvonne Elsworth·Rafael A. García·Gunter Houdek·Christoffer Karoff·Joanna Molenda-Żakowicz·Michael J. Thompson·Graham A. Verner·Guillermo Torres·Francois Fressin·Justin R. Crepp·Elisabeth Adams·Andrea Dupree·Dimitar D. Sasselov·Courtney D. Dressing·William J. Borucki·David G. Koch·Jack J. Lissauer·David W. Latham·Thomas N. Gautier III·Mark Everett·Elliott Horch·Natalie M. Batalha·Edward W. Dunham·Paula Szkody·David R. Silva·Ken Mighel·Jay Holberg·Jer^ome Ballot·Timothy R. Bedding·Hans Bruntt·Tiago L. Campante·Rasmus Handberg·Saskia Hekker·Daniel Huber·Savita Mathur·Benoit Mosser·Clara Régulo·Timothy R. White·Jessie L. Christiansen·Christopher K. Middour·Michael R. Haas·Jennifer R. Hall·Jon M. Jenkins·Sean McCaulif·Michael N. Fanelli·Craig Kulesa·Don McCarthy·Christopher E. Henze
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Abstract

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 frequencypower 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{\pm}0.06 M{\circ} and 1.86{\pm}0.04 R{\circ} respectively, as well as yielding an age of 2.84{\pm}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 (3{\sigma}) that the transit event is caused by a 1.64{\pm}0.04 R_Earth exoplanet in a 2.785755{\pm}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 (2-{\sigma}). HD 179070 is the brightest exoplanet host star yet discovered by Kepler.

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Steve B. Howell, Jason F. Rowe, Stephen T. Bryson, Samuel N. Quinn, Geoffrey W. Marcy, Howard Isaacson, David R. Ciardi, William J. Chaplin, Travis S. Metcalfe, Mario J. P. F. G. Monteiro, Thierry Appourchaux, Sarbani Basu, Orlagh L. Creevey, Ronald L. Gilliland, Pierre-Olivier Quirion, Denis Stello, Hans Kjeldsen, Jorgen Christensen-Dalsgaard, Yvonne Elsworth, Rafael A. García, Gunter Houdek, Christoffer Karoff, Joanna Molenda-Żakowicz, Michael J. Thompson, Graham A. Verner, Guillermo Torres, Francois Fressin, Justin R. Crepp, Elisabeth Adams, Andrea Dupree, Dimitar D. Sasselov, Courtney D. Dressing, William J. Borucki, David G. Koch, Jack J. Lissauer, David W. Latham, Thomas N. Gautier III, Mark Everett, Elliott Horch, Natalie M. Batalha, Edward W. Dunham, Paula Szkody, David R. Silva, Ken Mighel, Jay Holberg, Jer^ome Ballot, Timothy R. Bedding, Hans Bruntt, Tiago L. Campante, Rasmus Handberg, Saskia Hekker, Daniel Huber, Savita Mathur, Benoit Mosser, Clara Régulo, Timothy R. White, Jessie L. Christiansen, Christopher K. Middour, Michael R. Haas, Jennifer R. Hall, Jon M. Jenkins, Sean McCaulif, Michael N. Fanelli, Craig Kulesa, Don McCarthy, Christopher E. Henze. 2011-12-09. Kepler-21b: A 1.6REarth Planet Transiting the Bright Oscillating F Subgiant Star HD 179070. https://doi.org/10.1088/0004-637x%2F746%2F2%2F123

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