Analysis of time series of solar-like oscillations

The study of stellar oscillations allows one to constrain the structure and dynamics of stellar interiors to a precision that cannot be achieved with other methods. This dissertation focuses on the measurements of the parameters (frequencies, amplitudes, linewidths, and rotational splitting) of the global modes of solarlike oscillations observed in the Sun and in the Sun-like star HD 52265. The thesis is organized in three main parts: (i) an implementation and validation of a global fit of stellar oscillation power spectra using solar observations, (ii) an application of this method to original 4-month-long CoRoT observations of the planet-hosting, solar-like star HD 52265, and (iii) an extension of the fitting method to time series with gaps. The main results concern HD 52265: the mode frequencies of the radial, dipole and quadrupole modes are measured with the highest precision achieved so far for a solar-type star and, for the first time, the effect of rotation on oscillations in a solar-type star is measured unambiguously. Furthermore, the seismic constraint on the inclination angle of the stellar rotation axis allows us to estimate the absolute mass of the companion. Accordingly the seismic analysis strongly suggests that the companion is a planet and not a brown dwarf.