Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc--The Southern Sample

Abstract

We are obtaining spectra, spectral types, and basic physical parameters for the nearly 3600 dwarf and giant stars earlier than MO in the Hipparcos catalog within 40 pc of the Sun. Here we report on results for 1676 stars in the southern hemisphere observed at Cerro Tololo Inter-American Observatory and Steward Observatory. These results include new, precise, homogeneous spectral types, basic physical parameters (including the effective temperature, surface gravity, and metallicity [M/H]), and measures of the chromospheric activity of our program stars. We include notes on astrophysically interesting stars in this sample, the metallicity distribution of the solar neighborhood, and a table of solar analogs. We also demonstrate that the bimodal nature of the distribution of the chromospheric activity parameter log R HK′ depends strongly on the metallicity, and we explore the nature of the "low-metallicity" chromospherically active K-type dwarfs. © 2006. The American Astronomical Society. All rights reserved.