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Centro de Astrofísica da Universidade do Porto

A precise asteroseismic age and radius for the evolved Sun-like star KIC 11026764

T. S. Metcalfe, M. J. P. F. G. Monteiro, M. J. Thompson, J. Molenda-Żakowicz, T. Appourchaux, W. J. Chaplin, G. Doǧan, P. Eggenberger, T. R. Bedding, H. Bruntt, O. L. Creevey, P.-O. Quirion, D. Stello, A. Bonanno, V. Silva Aguirre, S. Basu, L. Esch, N. Gai, M. P. Di Mauro, A. G. Kosovichev, I. N. Kitiashvili, J.-C. Suárez, A. Moya Bedón, L. Piau, R. A. García, J. P. Marques, A. Frasca, K. Biazzo, S. G. Sousa, S. Dreizler, M. Bazot, C. Karoff, S. Frandsen, P. A. Wilson, T. M. Brown, J. Christensen-Dalsgaard, R. L. Gilliland, H. Kjeldsen, T. L. Campante, S. T. Fletcher, R. Handberg, C. Régulo, D. Salabert, J. Schou, G. A. Verner, J. Ballot, A.-M. Broomhall, Y. Elsworth, S. Hekker, D. Huber, S. Mathur, R. New, I. W. Roxburgh, K. H. Sato, T. R. White, W. J. Borucki, D. Koch, J. M. Jenkins

Abstract
The primary science goal of the Kepler Mission is to provide a census of exoplanets in the solar neighborhood, including the identification and characterization of habitable Earth-like planets. The asteroseismic capabilities of the mission are being used to determine precise radii and ages for the target stars from their solar-like oscillations. Chaplin et al. (2010) published observations of three bright G-type stars, which were monitored during the first 33.5 d of science operations. One of these stars, the subgiant KIC 11026764, exhibits a characteristic pattern of oscillation frequencies suggesting that it has evolved significantly. We have derived asteroseismic estimates of the properties of KIC 11026764 from Kepler photometry combined with ground-based spectroscopic data. We present the results of detailed modeling for this star, employing a variety of independent codes and analyses that attempt to match the asteroseismic and spectroscopic constraints simultaneously. We determine both the radius and the age of KIC 11026764 with a precision near 1%, and an accuracy near 2% for the radius and 15% for the age. Continued observations of this star promise to reveal additional oscillation frequencies that will further improve the determination of its fundamental properties.

Keywords
stars: evolution - stars: individual (KIC 11026764) - stars: interiors - stars: oscillations

The Astrophysical Journal
Volume 723, Page 1583
November 2010

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