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
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.
asteroseismology – methods: data analysis – stars: individual (KIC 11395018, KIC 11234888) – stars: oscillations – stars: solar-type
The Astrophysical Journal
Volume 733, Number 2, Page 95_1