Radial velocities of HD 209625

Indeed, stellar models including a detailed treatment of the radiative diffusion predict the existence of a near-surface convection zone in order to correctly reproduce the anomalies in surface abundances that are observed in Am stars. The Am star HD 209625 was observed with the Harps spectrograph mounted on the 3.6-m telescope at the ESO La Silla Observatory (Chile) during 9 nights in August 2005.

This observing run allowed to collect 1243 radial velocity measurements, with a standard deviation of 1.35m/s. The power spectrum associated with these RV measurements does not present any excess. Therefore, either the structure of the external layers of this star does not enable to excite solar-like oscillations, or the amplitudes of the oscillations remains below 20-30cm/s (depending of their frequency range).