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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Activity and differential rotation of the early M dwarf Kepler-45 from transit mapping

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Zaleski, S. M. [1] ; Valio, A. [2] ; Carter, B. D. [1] ; Marsden, S. C. [1]
Total Authors: 4
[1] Univ Southern Queensland, Ctr Astrophys, Toowoomba, Qld 4350 - Australia
[2] Univ Prebiteriana Mackenzie, Ctr Radio Astron & Astrophys, Rua Consolacao 896, BR-01302907 Sao Paulo, SP - Brazil
Total Affiliations: 2
Document type: Journal article
Source: Monthly Notices of the Royal Astronomical Society; v. 492, n. 4, p. 5141-5151, MAR 2020.
Web of Science Citations: 0

Little is known of the activity and differential rotation of low luminosity, early M dwarfs from direct observation. We present the first stellar activity analysis of star-spots and faculae for the hot Jupiter hosting M1V dwarf Kepler -45 from Kepler transit light curves. We find star-spot and facula temperatures contrasting a few hundred degrees with the quiet photosphere, hence similar to other early M dwarfs having a convective envelope surrounding a radiative core. Star-spots are prominent close to the centre of the stellar disc, with faculae prominent towards the limbs, similar to what is observed for the Sun. Star-spot and facula mean sizes are about 40 and 45 x 103 km, respectively, and thus faculae occupy a 10 per cent larger surface area than the star-spots. A short-term activity cycle of about 295 d is observed that is reminiscent of those seen for other cool dwarfs. Adopting a solar -type differential rotation profile (faster equatorial rotation than polar rotation), our star-spot and facula temporal mapping indicates a rotation period of 15,520 0,025 d at the transit latitude of -33.2', From the mean stellar rotation of 15,762 d, we estimate a rotational shear of 0.031 + 0,004 rad d 1, or a relative differential rotation 01'7.8 0.9 per cent., Kepler-45's surface rotational shear is thus consistent with observations and theoretical modelling of other early M dwarfs that indicate a shear of less than 0.045 rad d-1 and no less than 0,03 rad d-1 for stars with similar stellar rotation periods. (AU)

FAPESP's process: 13/10559-5 - Investigation of high energy and plasma astrophysics phenomena: theory, numerical simulations, observations, and instrument development for the Cherenkov Telescope Array (CTA)
Grantee:Elisabete Maria de Gouveia Dal Pino
Support type: Research Projects - Thematic Grants