The Space Interferometry Mission Astrometric Grid Giant-Star Survey. III. Basic Stellar Parameters for an Extended Sample

TL;DR

This study analyzes high-resolution spectra of 830 candidate red giants to determine their stellar parameters, confirming the effectiveness of the selection process and providing insights into their metallicity and elemental abundances.

Contribution

Developed an automated pipeline for stellar parameter estimation from spectra and validated its effectiveness on a large sample of red giants.

Findings

Most stars are G and K giants with slightly subsolar metallicity.

The [Mg/Fe] vs [Fe/H] trend aligns with previous studies.

High success rate in candidate selection confirmed.

Abstract

We present results of high resolution (~ 55000) spectral observations of 830 photometrically pre-selected candidate red giants in the magnitude range of V = 9-12. We develop a pipeline for automated determination of the stellar atmospheric parameters from these spectra and estimate T_eff, logg, [Fe/H], microturbulence velocity, and projected rotational velocities, vsini, for the stars. The analysis confirms that the candidate selection procedure yielded red giants with very high success rate. We show that most of these stars are G and K giants with slightly subsolar metallicity ([Fe/H] ~ -0.3 dex) An analysis of Mg abundances in the sample results in consistency of the [Mg/Fe] vs [Fe/H] trend with published results.