Stellar flares from blended and neighbouring stars in Kepler short cadence observations

TL;DR

This study investigates stellar flares from neighboring stars in Kepler data, revealing high-energy flares from faint stars, analyzing binary star activity, and estimating false positive rates for TESS data.

Contribution

It uncovers and characterizes flares from neighboring stars in Kepler data, including high-energy events, and assesses false positive rates in TESS observations.

Findings

Measured M dwarf flare energies up to 1.5×10^35 erg.

Found 6.7% of flares originate from neighboring stars.

Estimated 5.8% false positive rate in TESS flare studies.

Abstract

We present the results of a search for stellar flares from stars neighbouring the target sources in the Kepler short cadence data. These flares have been discarded as contaminants in previous surveys and therefore provide an unexplored resource of flare events, in particular high energy events from faint stars. We have measured M dwarf flare energies up to 1.5$\times$10^35 erg, pushing the limit for flare energies measured using Kepler data. We have used our sample to study theflaring activity of wide binaries, finding that the lower mass counterpart in a wide binary flares more often at a given energy. Of the 4430 flares detected in our original search, 298 came from a neighbouring star, a rate of 6.7$\pm$0.4 per cent for the Kepler short cadence lightcurves. We have used our sample to estimate a 5.8$\pm$0.1 per cent rate of false positive flare events in studies using TESS short cadence data.