The Sloan Digital Sky Survey Data Release 7 Spectroscopic M Dwarf Catalog I: Data

TL;DR

This paper presents a comprehensive spectroscopic catalog of over 70,000 M dwarfs from SDSS DR7, including spectral measurements, metallicity indicators, and activity assessments, with implications for understanding stellar and galactic properties.

Contribution

The first detailed spectroscopic catalog of SDSS DR7 M dwarfs with spectral types, metallicity, activity data, and identification of nearby late-type M dwarfs.

Findings

Spectral types assigned with high precision.

Identification of eight new nearby late-type M dwarfs.

Analysis of magnetic activity and metallicity correlations.

Abstract

We present a spectroscopic catalog of 70,841 visually inspected M dwarfs from the seventh data release of the Sloan Digital Sky Survey (SDSS). For each spectrum, we provide measurements of the spectral type, a number of molecular bandheads, and the H-alpha, H-beta, H-gamma, H-delta and Ca II K emission lines. In addition, we calculate the metallicity-sensitive parameter zeta and identify a relationship between zeta and the g-r and r-z colors of M dwarfs. We assess the precision of our spectral types (which were assigned by individual examination), review the bulk attributes of the sample, and examine the magnetic activity properties of M dwarfs, in particular those traced by the higher order Balmer transitions. Our catalog is cross-matched to Two Micron All Sky Survey (2MASS) infrared data, and contains photometric distances for each star. Lastly, we identify eight new late-type M dwarfs that are possibly within 25 pc of the Sun. Future studies will use these data to thoroughly examine magnetic activity and kinematics in late-type M dwarfs and examine the chemical and dynamical history of the local Milky Way.