Solar analogues and solar twins in the HARPS archive★

Abstract

We present 63 solar analogues and twins for which high signal-to-noise ratio (S/N) archival data are available for the High Accuracy Radial velocity Planet Searcher (HARPS) high-resolution spectrograph at the European Southern Observatory (ESO) 3.6-m telescope. We perform a differential analysis of these stellar spectra relative to the solar spectrum, similar to previous work using ESO 2.2-m/fiber-fed extended range optical spectrograph (FEROS) data, and expand our analysis by introducing a new method to test the temperature and metallicity calibration of Sun-like stars in the Geneva–Copenhagen Survey (GCS). The HARPS data are significantly better than the FEROS data, with improvements in S/N, spectral resolution and number of lines we can analyse. We confirm the offsets to the photometric scale found in our FEROS study. We confirm three solar twins found in the FEROS data as solar twins in the HARPS data, as well as identify six new twins.