The Sloan digital sky survey data release 7 spectroscopic m dwarf catalog iii: The spatial dependence of magnetic activity in the galaxy

TL;DR

This study examines how magnetic activity in M dwarfs varies across different regions of the galaxy, revealing a decrease with height above the galactic plane and an increase with distance from the galactic center, linked to stellar age.

Contribution

It provides the first detailed analysis of the spatial dependence of magnetic activity in M dwarfs across the galaxy using SDSS DR7 data.

Findings

Magnetic activity decreases with height above the galactic plane.

Activity fraction increases with Galactocentric radius.

Radial gradient in activity fraction linked to stellar age.

Abstract

We analyze the magnetic activity of 59,318 M dwarfs from the Sloan Digital Sky Survey (SDSS) Data Release 7. This analysis explores the spatial distribution of M dwarf activity as a function of both vertical distance from the Galactic plane (Z) and planar distance from the Galactic center (R). We confirm the established trends of decreasing magnetic activity (as measured by H-alpha emission) with increasing distance from the mid-plane of the disk and find evidence for a trend in Galactocentric radius. We measure a non-zero radial gradient in the activity fraction in our analysis of stars with spectral types dM3 and dM4. The activity fraction increases with R and can be explained by a decreasing mean stellar age with increasing distance from the Galactic center.