A fresh look at the seismic spectrum of HD49933: analysis of 180 days of CoRoT photometry
Abstract
Context: Solar-like oscillations have now been observed in several stars, thanks to ground-based spectroscopic observations and space-borne photometry. CoRoT, which has been in orbit since December 2006, has observed the star HD49933 twice. The oscillation spectrum of this star has proven difficult to interpret.
Aims: Thanks to a new timeseries provided by CoRoT, we aim to provide a robust description of the oscillations in HD49933, i.e., to identify the degrees of the observed modes, and to measure mode frequencies, widths, amplitudes and the average rotational splitting.
Methods: Several methods were used to model the Fourier spectrum: Maximum Likelihood Estimators and Bayesian analysis using Markov Chain Monte-Carlo techniques.
Results: The different methods yield consistent result, and allow us to make a robust identification of the modes and to extract precise mode parameters. Only the rotational splitting remains difficult to estimate precisely, but is clearly relatively large (several μHz in size).
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- November 2009
- DOI:
- 10.1051/0004-6361/200913111
- arXiv:
- arXiv:0910.3060
- Bibcode:
- 2009A&A...507L..13B
- Keywords:
-
- stars: oscillations;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 7 pages, 10 figures