The Kepler Catalog of Stellar Flares

TL;DR

This study systematically analyzed Kepler light curves to identify stellar flares, creating a large catalog that reveals how flare activity correlates with stellar properties and rotation, and introduces new tools for flare detection.

Contribution

It provides a comprehensive, homogeneous catalog of stellar flares from Kepler data and introduces publicly available tools for flare detection and completeness assessment.

Findings

Detected 851,168 flare events from 4041 stars.

Found flare activity increases with decreasing stellar mass.

Observed potential saturation of flare activity in rapidly rotating low-mass stars.

Abstract

A homogeneous search for stellar flares has been performed using every available Kepler light curve. An iterative light curve de-trending approach was used to filter out both astrophysical and systematic variability to detect flares. The flare recovery completeness has also been computed throughout each light curve using artificial flare injection tests, and the tools for this work have been made publicly available. The final sample contains 851,168 candidate flare events recovered above the 68% completeness threshold, which were detected from 4041 stars, or 1.9% of the stars in the Kepler database. The average flare energy detected is ~$10^{35}$ erg. The net fraction of flare stars increases with $g-i$ color, or decreasing stellar mass. For stars in this sample with previously measured rotation periods, the total relative flare luminosity is compared to the Rossby number. A tentative detection of flare activity saturation for low-mass stars with rapid rotation below a Rossby number of ~0.03 is found. A power law decay in flare activity with Rossby number is found with a slope of -1, shallower than typical measurements for X-ray activity decay with Rossby number.