Short-period Stellar Activity Cycles with Kepler Photometry

Author(s): O. V. Arkhypov, Maxim L. Khodachenko, Helmut Lammer, Manuel Güdel, Theresa Rank-Lüftinger, Colin Johnstone
Abstract: We study the short-periodic component of stellar activity with a cycle period of P_cyc\lt 10³ days using the Kepler mission photometry of fast-rotating (1\lt P\lt 4 days) stars with spectra of M4V to F3V. Applying the originally developed two non-spectral methods, we measured the effective period of stellar cycles in 462 objects. The obtained results are in accordance with previous measurements by Vida et al. and do not seem to result from a beating effect. The performed measurements of P_cyc cluster in a specific branch that covers the previously unstudied region in the Saar & Brandenburg diagram and connects the branch of inactive stars with the area populated by super-active objects. It is shown that the formation of the discovered branch is due to the α-quenching effect, which saturates the magnetic dynamo and decreases the cycle periods with the increase of the inverted Rossby number. This finding is important in the context of the discussion on catastrophic quenching and other heuristic approximations of the nonlinear α-effect.
Organisation(s): Department of Astrophysics
External organisation(s): Österreichische Akademie der Wissenschaften (ÖAW)
Journal: The Astrophysical Journal
Volume: 807
No. of pages: 15
ISSN: 0004-637X
DOI: https://doi.org/10.1088/0004-637X/807/1/109
Publication date: 07-2015
Peer reviewed: Yes
Austrian Fields of Science 2012: 103003 Astronomy, 103004 Astrophysics
Keywords
ASJC Scopus subject areas: Astronomy and Astrophysics, Space and Planetary Science
Portal url: https://ucrisportal.univie.ac.at/en/publications/shortperiod-stellar-activity-cycles-with-kepler-photometry(2a610a23-af78-41fc-9ac8-eb5f2dd4862a).html

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