Solar-like oscillations with low amplitude in the CoRoT target HD 181906
Abstract
Context: The F8 star HD 181906 (effective temperature ~6300K) was observed for 156 days by the CoRoT satellite during the first long run in the centre direction. Analysis of the data reveals a spectrum of solar-like acoustic oscillations. However, the faintness of the target (m_v=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: To 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 have been 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 have been 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 microHz) with indications of the presence of surface differential rotation, the large separation of the p modes (~87 microHz), and therefore also the ridges corresponding to overtones of the acoustic modes.
Keywords
Cite
@article{arxiv.0907.0608,
title = {Solar-like oscillations with low amplitude in the CoRoT target HD 181906},
author = {R. A. Garcia and C. Regulo and R. Samadi and J. Ballot and C. Barban and O. Benomar and W. J. Chaplin and P. Gaulme and T. Appourchaux and S. Mathur and B. Mosser and T. Toutain and G. A. Verner and M. Auvergne and A. Baglin and F. Baudin and P. Boumier and H. Bruntt and C. Catala and S. Deheuvels and Y. Elsworth and S. J. Jimenez-Reyes and E. Michel and F. Perez Hernandez and I. W. Roxburgh and D. Salabert},
journal= {arXiv preprint arXiv:0907.0608},
year = {2009}
}
Comments
Paper Accepted to be published in A&A. 10 Pages, 12 figures