摘要：Context.The presence and strength of a stellar magnetic field and activity is rooted in a star’s fundamental parameters such as mass and age. Can flares serve as an accurate stellar “clock”?Aims.To explore if we can quantify an activity-age relation in the form of a flaring-age relation, we measured trends in the flaring rates and energies for stars with different masses and ages.Methods.We investigated the time-domain photometry provided byKepler’sfollow-up mission K2 and searched for flares in three solar metallicity open clusters with well-known ages, M 45 (0.125 Gyr), M 44 (0.63 Gyr), and M 67 (4.3 Gyr). We updated and employed the automated flare finding and analysis pipelineAppaloosa, originally designed forKepler. We introduced a synthetic flare injection and recovery sub-routine to ascribe detection and energy recovery rates for flares in a broad energy range for each light curve.Results.We collect a sample of 1761 stars, mostly late-K to mid-M dwarfs and found 751 flare candidates with energies ranging from 4 × 1032erg to 6 × 1034erg, of which 596 belong to M 45, 155 to M 44, and none to M 67. We find that flaring activity depends both onTeff, and age. But all flare frequency distributions have similar slopes withα ≈ 2.0−2.4, supporting a universal flare generation process. We discuss implications for the physical conditions under which flares occur, and how the sample’s metallicity and multiplicity affect our results.
关键词：enmethods: data analysisstars: activitystars: flarestars: low-mass
