Flares in Open Clusters with K2. I. M45 (Pleiades), M44 (Praesepe) and M67

Abstract

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"? 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. We investigated the time-domain photometry provided by Kepler's follow-up mission K2 and searched for flares in three solar metallicity open clusters with well-known ages, M45 (0.125 Gyr), M44 (0.63 Gyr), and M67 (4.3 Gyr). We updated and employed the automated flare finding and analysis pipeline Appaloosa, originally designed for Kepler. We introduced a synthetic flare injection and recovery subroutine to ascribe detection and energy recovery rates for flares in a broad energy range for each light curve. We collected a sample of 1 761 stars, mostly late-K to mid-M dwarfs and found 751 flare candidates with energies ranging from $4\cdot 10^{32}$ erg to $6\cdot 10^{34}$ erg, of which 596 belong to M45, 155 to M44, and none to M67. We find that flaring activity depends both on $T_{\mathrm{eff}}$, and age. But all flare frequency distributions have similar slopes with $\alpha \approx 2.0-2.4$, 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.

17 pages, 11 figures, appendix. Accepted to A&A

References in corpus (32)

• The NumPy array: a structure for efficient numerical computation
• The Transiting Exoplanet Survey Satellite
• The K2 Mission: Characterization and Early results
• Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Southern Sample
• Stellar magnetism: empirical trends with age and rotation
• Stellar SEDs from 0.3-2.5 Microns: Tracing the Stellar Locus and Searching for Color Outliers in SDSS and 2MASS
• Kepler Flares I. Active and Inactive M dwarfs
• The Kepler Catalog of Stellar Flares
• The Stellar Populations of Praesepe and Coma Berenices
• Precision Stellar Characterization of FGKM Stars using an Empirical Spectral Library
• Kepler Flares II: The Temporal Morphology of White-Light Flares on GJ 1243
• A spin-down clock for cool stars from observations of a 2.5-billion-year-old cluster
• EVEREST: Pixel Level Decorrelation of K2 Light curves
• The Solar Neighborhood XXXVII: The Mass-Luminosity Relation for Main Sequence M Dwarfs
• Solar-type dynamo behaviour in fully convective stars without a tachocline
• HAZMAT I: The Evolution of Far-UV and Near-UV Emission from Early M Stars
• Main-Sequence Effective Temperatures from a Revised Mass-Luminosity Relation Based on Accurate Properties
• On differential rotation and overshooting in solar-like stars
• The Factory and The Beehive II. Activity and Rotation in Praesepe and the Hyades
• M Dwarfs in SDSS Stripe 82: Photometric Light Curves and Flare Rate Analysis
• Ground-based CCD astrometry with wide field imagers. II. A star catalogue for M67: [email protected] MPG/ESO astrometry, FLAMES@VLT radial velocities
• On the magnetic topology of partially and fully convective stars
• Hubble Space Telescope Spectroscopy of Brown Dwarfs Discovered with the Wide-field Infrared Survey Explorer
• Superflare occurrence and energies on G-, K- and M-type dwarfs
• Near-infrared photometry of Y dwarfs: low ammonia abundance and the onset of water clouds
• The Seven Sisters DANCe. I. Empirical isochrones, Luminosity and Mass Functions of the Pleiades cluster
• Stellar flares observed in long cadence data from the Kepler mission
• The influence of metallicity on stellar differential rotation and magnetic activity
• A Sensitive Identification of Warm Debris Disks in the Solar Neighborhood Through Precise Calibration of Saturated WISE Photometry
• Kepler Flares III: Stellar Activity on GJ 1245 A and B
• The age-mass-metallicity-activity relation for solar-type stars: Comparisons with asteroseismology and the NGC 188 open cluster
• CCD Parallaxes for 309 Late-type Dwarfs and Subdwarfs

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• Superflares on the late-type giant KIC 2852961 -- Scaling effect behind flaring at different energy levels
• Stellar flares from blended and neighbouring stars in Kepler short cadence observations
• NGTS clusters survey -- II. White-light flares from the youngest stars in Orion
• Differences in radio emission from similar M dwarfs in the binary system Ross 867-8
• $\pi$ Earth: a 3.14-day Earth-sized Planet from $\text{K2}$'s Kitchen Served Warm by the SPECULOOS Team