Superflares On Solar-type Stars From The First Year Observation Of TESS

©NASA

Solar flare on our sun

Superflares, as strong explosions on stars, have been well studied with the progress of space time-domain astronomy. In this work, we present the study of superflares on solar-type stars using Transiting Exoplanet Survey Satellite ({\em{TESS}}) data.

13 sectors of observations during the first year of the {\em TESS} mission have covered the southern hemisphere of the sky, containing 25,734 solar-type stars. We verified 1,216 superflares on 400 solar-type stars through automatic search and visual inspection with 2-minute cadence data. Our result suggests a higher superflare frequency distribution than the result from {\em Kepler}. The reason may be that the majority of {\em TESS} solar-type stars in our dataset are rapidly rotating stars. The power-law index γ of the superflare frequency distribution (dN/dE∝E−γ) is constrained to be γ=2.16±0.10, which is a little larger than that of solar flares but consistent with the results from {\em Kepler}. Because only 7 superflares of Sun-like stars are detected, we may not give a robust superflare occurrence frequency. And four stars are accompanied by unconfirmed hot planet candidates. Therefore, superflares are possibly caused by stellar magnetic activities instead of planet-star interactions.

We also find an extraordinary star TIC43472154, which exhibits about 200 superflares per year. In addition, the correlation between energy and duration of superflares (Tduration ∝Eβ) is analyzed. We derive the power-law index to be β=0.42±0.01, which is a little larger than β=1/3 from the prediction according to magnetic reconnection theory.

Zuo-Lin Tu, Ming Yang, Z. J. Zhang, F. Y. Wang
(Submitted on 25 Dec 2019)

Comments: Accepted for Publication in ApJ. Comments are welcome
Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:1912.11572 [astro-ph.SR] (or arXiv:1912.11572v1 [astro-ph.SR] for this version)
Submission history
From: Zuolin Tu
[v1] Wed, 25 Dec 2019 01:42:50 UTC (719 KB)
https://arxiv.org/abs/1912.11572
Astrobiology, Space Weather

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