Accurate p-mode measurements of the G0V metal-rich CoRoT target HD 52265

The fundamental stellar parameters of HD 52265 were derived with the semi-automatic software VWA, and the projected rotational velocity was estimated by fitting synthetic profiles to isolated lines in the observed spectrum. The parameters of the observed p modes were determined with a maximum-likelihood estimation. We performed a global fit of the oscillation spectrum, over about ten radial orders, for degrees l = 0 to 2.

We also derived the properties of the granulation, and analysed a signature of the rotation induced by the photospheric magnetic activity. Results. Precise determinations of fundamental parameters have been obtained: T(eff) = 6100 ±-60K, log g = 4.35 ±-0.09, [M/H] = 0.19 ±-0.05, as well as v sin i = 3.6(₋₁.₀)(⁺⁰.³) km s(⁻¹).

We have measured a mean rotation period P(rot) = 12.3 +/- 0.15 days, and find a signature of differential rotation. The frequencies of 31 modes are reported in the range 1500-2550 mu Hz. The large separation exhibits a clear modulation around the mean value Δv = 98.3 ±-0.1 μHz.

Mode widths vary with frequency along an S-shape with a clear local maximum around 1800 μHz. We deduce lifetimes ranging between 0.5 and 3 days for these modes. Finally, we find a maximal bolometric amplitude of about 3.96 ±-0.24 ppm for radial modes.