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Centro de Astrofísica da Universidade do Porto

Solar-like oscillations in KIC 11395018 and KIC 11234888 from 8 months of Kepler data

S. Mathur, R. Handberg, T. L. Campante, R. A. García, T. Appourchaux, T. R. Bedding, B. Mosser, W. J. Chaplin, J. Ballot, O. Benomar, A. Bonanno, E. Corsaro, P. Gaulme, S. Hekker, C. Régulo, D. Salabert, G. A. Verner, T. R. White, I. M. Brandão, O. L. Creevey, G. Doǧan, Y. Elsworth, D. Huber, S. J. Hale, G. Houdek, C. Karoff, T. S. Metcalfe, J. Molenda-Żakowicz, M. J. P. F. G. Monteiro, M. J. Thompson, J. Christensen-Dalsgaard, R. L. Gilliland, S. D. Kawaler, H. Kjeldsen, E. V. Quintana, D. T. Sanderfer, S. E. Seader

Abstract
We analyze the photometric short-cadence data obtained with the Kepler mission during the first 8 months of observations of two solar-type stars of spectral types G and F: KIC 11395018 and KIC 11234888, respectively, the latter having a lower signal-to-noise ratio (S/N) compared with the former. We estimate global parameters of the acoustic (p) modes such as the average large and small frequency separations, the frequency of the maximum of the p-mode envelope, and the average line width of the acoustic modes. We were able to identify and to measure 22 p-mode frequencies for the first star and 16 for the second one even though the S/N of these stars are rather low. We also derive some information about the stellar rotation periods from the analyses of the low-frequency parts of the power spectral densities. A model-independent estimation of the mean density, mass, and radius is obtained using the scaling laws. We emphasize the importance of continued observations for the stars with low S/N for an improved characterization of the oscillation modes. Our results offer a preview of what will be possible for many stars with the long data sets obtained during the remainder of the mission.

Keywords
asteroseismology – methods: data analysis – stars: individual (KIC 11395018, KIC 11234888) – stars: oscillations – stars: solar-type

The Astrophysical Journal
Volume 733, Page 95_1
June 2011

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