Solar-like oscillations in the G8 V star τ Ceti

T. C. Teixeira, H. Kjeldsen, T. R. Bedding, F. Bouchy, J. Christensen-Dalsgaard, M. S. Cunha, T. Dall, S. Frandsen, C. Karoff, M. J. P. F. G. Monteiro, F. P. Pijpers

Abstract
We used HARPS to measure oscillations in the low-mass star τ Cet. Although the data  were compromised by instrumental noise, we have been able to extract the main features of the oscillations. We found τ Cet to oscillate with an amplitude that is about  half that of the Sun, and with a mode lifetime that is slightly shorter than solar. The large frequency  separation is 169 μHz, and we have identified modes with degrees 0, 1, 2, and 3. We  used the frequencies to estimate the mean density of the star to an accuracy of 0.45%  which, combined with the interferometric radius, gives a mass of 0.783 ± 0.012 M_⊙ (1.6%).

Keywords
stars: oscillations - stars: individual: τ Ceti - stars: individual: δ Pavonis - stars: individual: α Centauri B

Notes
Based on observations collected at the European Southern Observatory, La Silla, Chile (ESO Programme 74.D-0380).

Astronomy and Astrophysics
Volume 494, Page 237
January 2009

DOI: 10.1051/0004-6361:200810746
ADS Bibliographic code: 2009A%26A...494..237T