Statistical Parallax Analysis of SDSS M Dwarfs

TL;DR

This study uses a statistical parallax method on ~22,000 SDSS M dwarfs to determine their absolute magnitudes and kinematic properties, revealing new relations and insights into stellar activity, metallicity, and motion.

Contribution

It introduces new spectral type-absolute magnitude and color-absolute magnitude relations for M dwarfs based on SDSS data, improving understanding of their properties.

Findings

Active stars are brighter and younger stars have smaller velocity dispersions.

Metal-poor stars are fainter at a given spectral type.

Distant stars exhibit larger peculiar velocities.

Abstract

We report on the analysis of ~22,000 M dwarfs using a statistical parallax method. This technique employs a maximum-likelihood formulation to simultaneously solve for the absolute magnitude, velocity ellipsoid parameters and reflex solar motion of a homogeneous stellar sample, and has previously been applied to Galactic RR Lyrae and Cepheid populations and to the Palomar/Michigan State University (PMSU) survey of nearby low-mass stars. We analyze subsamples of the most recent spectroscopic catalog of M dwarfs in the Sloan Digital Sky Survey (SDSS) to determine absolute magnitudes and kinematic properties as a function of spectral type, color, chromospheric activity and metallicity. We find new, independent spectral type-absolute magnitude relations, and color-absolute magnitude relations in the SDSS filters, and compare to those found from other methods. Active stars have brighter absolute magnitudes and lower metallicity stars have fainter absolute magnitudes for stars of type M0-M4. Our kinematic analysis confirms previous results for the solar motion and velocity dispersions, with more distant stars possessing larger peculiar motions, and chromospherically active (younger) stars having smaller velocity dispersions than their inactive counterparts. We find some evidence for systematic differences in the mean U and W velocities of samples subdivided by color.