Chromospheric activity of Southern Stars from the Magellan Planet Search Program

Abstract: I present chromospheric activity measurements of ~ 670 F, G, K and M main sequence stars in the Southern Hemisphere, from ~8000 archival high-resolution echelle spectra taken at Las Campanas Observatory since 2004. These stars were targets from the Old Magellan Planet Search, and are now potential targets for the New Magellan Planet Search that will look for rocky and habitable planets. Activity indexes (S-values) are derived from Ca II H & K line cores and then converted to the Mt. Wilson system. From these measurements, chromospheric (logrhk) indexes are derived, which are then used as indicators of the level of radial-velocity jitter, age and rotation periods these stars present.