Flare stars in nearby Galactic open clusters based on {\it TESS} data

TL;DR

This study used TESS data to identify and analyze flare stars in 136 nearby Galactic open clusters, discovering 56 flare stars across various spectral types and examining their flare characteristics and rotation periods.

Contribution

It is the first large-scale survey of flare stars in open clusters using TESS data, applying the FLATW'RM algorithm for flare detection and characterization.

Findings

56 flare stars identified, including 8 hot B-A types.

63% of flares detected in cool stars (T_eff<5000K).

No clear correlation between age, rotation, and flaring activity.

Abstract

The study is devoted to search for flare stars among confirmed members of Galactic open clusters using high-cadence photometry from {\it TESS} mission. We analyzed 957 high-cadence light curves of members from 136 open clusters. As a result, 56 flare stars were found, among them 8 hot B-A type objects. Of all flares, 63\% were detected in a sample of cool stars ($T_{\rm eff}<5000$~K), and 29\% -- in stars of spectral type G, while 23\% in K-type stars and approximately 34\% of all detected flares are in M-type stars. Using the FLATW'RM (FLAre deTection With Ransac Method) flare finding algorithm, we estimated parameters of flares and rotation period of detected flare stars. The flare with the largest amplitude appears on the M3 type EQ\,Cha star. Statistical analysis did not reveal any direct correlation between ages, rotation periods and flaring activity.