Complex Rotational Modulation of Rapidly Rotating M Stars Observed with TESS
Name
Zhan_2019_ApJ_876_127.pdf
Description
Published version
Size
2.74 MB
Format
Adobe PDF
Checksum (MD5)
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Author(s)
Zhan, Zhuchang
Guenther, Maximilian N.
Rappaport, Saul A
Olah, K.
Levine, Alan M.
Winn, J.
Dai, F.
Zhou, G.
Huang, Chelsea
Bouma, L. G.
Date Issued
May 2019
Journal
Astrophysical Journal
Publisher
American Astronomical Society
Citation
Zhan, Z., et al. “Complex Rotational Modulation of Rapidly Rotating M Stars Observed with TESS.” The Astrophysical Journal 876, 2 (May 2019): 127. © 2019 The American Astronomical Society
Version
Final published version
Abstract
We have searched for short periodicities in the light curves of stars with T eff cooler than 4000 K made from 2-minute cadence data obtained in Transiting Exoplanet Survey Satellite sectors 1 and 2. Herein we report the discovery of 10 rapidly rotating M dwarfs with highly structured rotational modulation patterns among 371 M dwarfs found to have rotation periods less than 1 day. Starspot models cannot explain the highly structured periodic variations that typically exhibit between 10 and 40 Fourier harmonics. A similar set of objects was previously reported following K2 observations of the Upper Scorpius association. We examine the possibility that the unusual structured light curves could stem from absorption by charged dust particles that are trapped in or near the stellar magnetosphere. We also briefly explore the possibilities that the sharp structured features in the light curves are produced by extinction by coronal gas, by beaming of the radiation emitted from the stellar surface, or by occultations of spots by a dusty ring that surrounds the star. The last is perhaps the most promising of these scenarios. Most of the structured rotators display flaring activity, and we investigate changes in the modulation pattern following the largest flares. As part of this study, we also report the discovery of 17 rapidly rotating M dwarfs with rotational periods below 4 hr, of which the shortest period is 1.63 hr. Key words: circumstellar matter – stars: flare – stars: low-mass – stars: pre-main sequence – stars: variables:
general – starspots
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Massachusetts Institute of Technology. Department of Physics
MIT Kavli Institute for Astrophysics and Space Research
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DOI of Published Version
https://doi.org/10.3847/1538-4357/AB158C
