Stellar Flares from the First Tess Data Release: Exploring a New Sample of M-dwarfs

Kavli Affiliate: Saul Rappaport

| First 5 Authors: Maximilian N. G√ľnther, Zhuchang Zhan, Sara Seager, Paul B. Rimmer, Sukrit Ranjan

| Summary:

We perform a study of stellar flares for the 24,809 stars observed with 2
minute cadence during the first two months of the TESS mission. Flares may
erode exoplanets’ atmospheres and impact their habitability, but might also
trigger the genesis of life around small stars. TESS provides a new sample of
bright dwarf stars in our galactic neighborhood, collecting data for thousands
of M-dwarfs that might host habitable exoplanets. Here, we use an automated
search for flares accompanied by visual inspection. Then, our public
allesfitter code robustly selects the appropriate model for potentially complex
flares via Bayesian evidence. We identify 1228 flaring stars, 673 of which are
M-dwarfs. Among 8695 flares in total, the largest superflare increased the
stellar brightness by a factor of 16.1. Bolometric flare energies range from
10^31.0 to 10^36.9 erg, with a median of 10^33.1 erg. Furthermore, we study the
flare rate and energy as a function of stellar type and rotation period. We
solidify past findings that fast rotating M-dwarfs are the most likely to
flare, and that their flare amplitude is independent of the rotation period.
Finally, we link our results to criteria for prebiotic chemistry, atmospheric
loss through coronal mass ejections, and ozone sterilization. Four of our
flaring M dwarfs host exoplanet candidates alerted on by TESS, for which we
discuss how these effects can impact life. With upcoming TESS data releases,
our flare analysis can be expanded to almost all bright small stars, aiding in
defining criteria for exoplanet habitability.

| Search Query: ArXiv Query: search_query=au:”Saul Rappaport”&id_list=&start=0&max_results=10

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