Chromospheric activity of Southern Stars from the Magellan Planet Search Program

TL;DR

This study measures chromospheric activity in about 670 Southern Hemisphere stars using archival spectra, providing data crucial for exoplanet searches and understanding stellar properties.

Contribution

It offers a large dataset of chromospheric activity indices for a diverse set of stars, aiding in the selection of stable targets for planet detection.

Findings

Chromospheric activity levels vary across spectral types.

Activity indices correlate with stellar age and rotation.

Data supports improved target selection for exoplanet surveys.

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.