2005A&A...429L..17C

We present high precision radial velocity measurements on the F5 IV star α CMi obtained by the SARG spectrograph at TNG (Telescopio Nazionale Galileo) exploiting the iodine cell technique. The time series of about 950 spectra of Procyon A taken during 6 observation nights are affected by an individual error of 1.3m/s. Thanks to the iodine cell technique, the spectrograph contribution to the Doppler shift measurement error is quite negligible and our error is dominated by the photon statistics (Brown et al., 1994PASP..106.1285B. An excess of power between 0.5 and 1.5mHz, detected also by Martic et al. (2004A&A...418..295M) has been found. We determined a large separation frequency Δν₀=56±2µHz, consistent with both theoretical estimates (Chaboyer et al., 1999ApJ...525L..41C) and previous observations Martic et al. (2004A&A...418..295M).