Mining Databases for M Dwarf Variability

TL;DR

This study analyzes infrared time-series data of 4343 M dwarfs from SDSS and 2MASS to detect stellar flares, revealing significant variability consistent with flare activity in infrared bands.

Contribution

It introduces a modified variability index and demonstrates infrared flare detection in M dwarfs using large multi-epoch datasets.

Findings

Infrared variability shows power-law slopes of -3.37 (JH) and -4.05 (HKs).

Evidence of stellar flares observed in infrared photometry.

Large sample analysis confirms infrared flare activity in M dwarfs.

Abstract

Time-resolved databases with large spatial coverage are quickly becoming a standard tool for all types of astronomical studies. We report preliminary results from our search for stellar flares in the 2MASS calibration fields. A sample of 4343 M dwarfs, spatially matched between the SDSS and the 2MASS calibration fields, each with hundreds to thousands of epochs in near infrared bandpasses, is analyzed using a modified Welch-Stetson index to characterize the variability. A Monte Carlo model was used to assess the noise of the variability index. We find significnat residuals above the noise with power-law slopes of -3.37 and -4.05 for our JH and HKs distributions respectively. This is evidence for flares being observed from M dwarfs in infrared photometry.