Solar-like oscillations with low amplitude in the CoRoT target HD 181906

R. A. García, C. Régulo, R. Samadi, J. Ballot, C. Barban, O. Benomar, W. J. Chaplin, P. Gaulme, T. Appourchaux, S. Mathur, B. Mosser, T. Toutain, G. A. Verner, M. Auvergne, A. Baglin, F. Baudin, P. Boumier, H. Bruntt, C. Catala, S. DeheuvelsY. Elsworth, S. J. Jiménez-Reyes, E. Michel, F. Pérez Hernández, I. W. Roxburgh, D. Salabert

Research output: Contribution to journalArticlepeer-review

Abstract

Context. The F8 star HD 181906 (effective temperature ∼6300 K) was observed for 156 days by the CoRoT satellite during the first long run in the direction of the galactic centre. Analysis of the data reveals a spectrum of solar-like acoustic oscillations. However, the faintness of the target (mν = 7.65) means the signal-to-noise (S/N) in the acoustic modes is quite low, and this low S/N leads to complications in the analysis. Aims. We extract global variables of the star, as well as key parameters of the p modes observed in the power spectrum of the lightcurve. Methods. The power spectrum of the lightcurve, a wavelet transform and spot fitting were used to obtain the average rotation rate of the star and its inclination angle. Then, the autocorrelation of the power spectrum and the power spectrum of the power spectrum were used to properly determine the large separation. Finally, estimations of the mode parameters were done by maximizing the likelihood of a global fit, where several modes were fit simultaneously. Results. We have been able to infer the mean surface rotation rate of the star (∼4 μHz) with indications of the presence of surface differential rotation, the large separation of the p modes (∼87 μHz), hence also the "ridges" corresponding to overtones of the acoustic modes.

Original languageEnglish (US)
Pages (from-to)41-50
Number of pages10
JournalAstronomy and Astrophysics
Volume506
Issue number1
DOIs
StatePublished - 2009

Keywords

  • Methods: observational
  • Methods: statistical
  • Stars: individual: HD 181906
  • Stars: oscillations

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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