Spots and flares in hot main sequence stars observed by Kepler, K2 and TESS
Abstract
About 22000 Kepler stars, 7000 K2 stars and nearly 60000 TESS stars from sectors 1-24 have been classified according to variability type. A large proportion of stars of all spectral types appear to have periods in their light curves consistent with the expected rotation periods. A previous analysis of A- and late B-type stars suggests that these stars are indeed rotational variables. In this paper we have accumulated data to show that rotational modulation is present in about 30-40 percent of A- and B-type stars. A search for flares in TESS A- and B-type stars resulted in the detection of 102 flares in 57 stars. Analysis of flare energies show that the source of the flares cannot be a cool dwarf companion nor a F/G giant. The realization that a considerable fraction of A- and B-type stars are active indicates that a revision of current concepts regarding hot star envelopes is required.
- Publication:
-
Frontiers in Astronomy and Space Sciences
- Pub Date:
- March 2021
- DOI:
- 10.3389/fspas.2021.580907
- Bibcode:
- 2021FrASS...8...32B
- Keywords:
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- Stellar activity;
- stellar rotation;
- star spots;
- flare stars;
- time series