Solar-like Oscillations in KIC 11395018 and KIC 11234888 from 8 Months of Kepler Data
Savita Mathur
(1)
,
Rasmus Handberg
(2)
,
Tiago L. Campante
(3)
,
Rafael A. Garcia
(4)
,
Thierry Appourchaux
(5)
,
Timothy R. Bedding
(6)
,
Benoît Mosser
(7, 8)
,
William J. Chaplin
(9)
,
Jérôme Ballot
(10)
,
Othman Benomar
(5)
,
Alfio Bonanno
(11)
,
Enrico Corsaro
(11)
,
Patrick Gaulme
(5)
,
Saskia Hekker
(9)
,
Clara Regulo
(12)
,
David Salabert
(12)
,
Graham A. Verner
(13)
,
Timothy R. White
(6)
,
I. M. Brandão
(3)
,
Orlagh L. Creevey
(12)
,
Gülnur Dogan
(2)
,
Yvonne P. Elsworth
(9)
,
Daniel Huber
(6)
,
S. J. Hale
(9)
,
Günter Houdek
(14)
,
Christoffer Karoff
(2)
,
Travis S. Metcalfe
(1)
,
Joanna Molenda-Zakowicz
(15)
,
M. J. P. F. G. Monteiro
(3)
,
Michael J. Thompson
(1)
,
Jörgen Christensen-Dalsgaard
(2)
,
Ronald L. Gilliland
(16)
,
Steven D. Kawaler
(17)
,
Hans Kjeldsen
(2)
,
E. V. Quintana
(18)
,
Dwight T. Sanderfer
(18)
,
S. E. Seader
(18)
1
High Altitude Observatory, National Center for Atmospheric Research
2 DASC - Danish AsteroSeismology Centre
3 Universidade do Porto = University of Porto
4 CEA - Commissariat à l'énergie atomique et aux énergies alternatives
5 IAS - Institut d'astrophysique spatiale
6 SIfA - Sydney Institute for Astronomy
7 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
8 Pôle Planétologie du LESIA
9 University of Birmingham [Birmingham]
10 IRAP - Institut de recherche en astrophysique et planétologie
11 INAF-OACt - INAF-Osservatorio Astrofisico di Catania
12 ULL - Universidad de La Laguna [Tenerife - SP]
13 School of Mathematical Sciences, Queen Mary Unversity of London
14 IfA - Institut für Astronomie, Universität Wien
15 Astronomical Institute, University of Wroclaw
16 STSci - Space Telescope Science Institute
17 ISU - Iowa State University
18 SETI Institute, NASA Ames Research Center, Moffett Field
2 DASC - Danish AsteroSeismology Centre
3 Universidade do Porto = University of Porto
4 CEA - Commissariat à l'énergie atomique et aux énergies alternatives
5 IAS - Institut d'astrophysique spatiale
6 SIfA - Sydney Institute for Astronomy
7 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
8 Pôle Planétologie du LESIA
9 University of Birmingham [Birmingham]
10 IRAP - Institut de recherche en astrophysique et planétologie
11 INAF-OACt - INAF-Osservatorio Astrofisico di Catania
12 ULL - Universidad de La Laguna [Tenerife - SP]
13 School of Mathematical Sciences, Queen Mary Unversity of London
14 IfA - Institut für Astronomie, Universität Wien
15 Astronomical Institute, University of Wroclaw
16 STSci - Space Telescope Science Institute
17 ISU - Iowa State University
18 SETI Institute, NASA Ames Research Center, Moffett Field
Résumé
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.