Differential rotation of Kepler-71 via transit photometry mapping of faculae and starspots
Article
Article Title | Differential rotation of Kepler-71 via transit photometry mapping of faculae and starspots |
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ERA Journal ID | 1074 |
Article Category | Article |
Authors | Zaleski, S. M. (Author), Valio, A. (Author), Marsden, S. C. (Author) and Carter, B. D. (Author) |
Journal Title | Monthly Notices of the Royal Astronomical Society |
Journal Citation | 484 (1), pp. 618-630 |
Number of Pages | 13 |
Year | 2019 |
Publisher | Oxford University Press |
Place of Publication | United Kingdom |
ISSN | 0035-8711 |
1365-2966 | |
Digital Object Identifier (DOI) | https://doi.org/10.1093/mnras/sty3474 |
Web Address (URL) | https://academic.oup.com/mnras/article/484/1/618/5289895 |
Abstract | Knowledge of dynamo evolution in solar-type stars is limited by the difficulty of using active region monitoring to measure stellar differential rotation, a key probe of stellar dynamo physics. This paper addresses the problem by presenting the first ever measurement of stellar differential rotation for a main-sequence solar-type star using starspots and faculae to provide complementary information. Our analysis uses modelling of light curves of multiple exoplanet transits for the young solar-type star Kepler-71, utilizing archival data from the Kepler mission. We estimate the physical characteristics of starspots and faculae on Kepler-71 from the characteristic amplitude variations they produce in the transit light curves and measure differential rotation from derived longitudes. Despite the higher contrast of faculae than those in the Sun, the bright features on Kepler-71 have similar properties such as increasing contrast towards the limb and larger sizes than sunspots. Adopting a solar-type differential rotation profile (faster rotation at the equator than the poles), the results from both starspot and facula analysis indicate a rotational shear less than about 0.005 rad d-1, or a relative differential rotation less than 2 per cent, and hence almost rigid rotation. This rotational shear contrasts with the strong rotational shear of zero-age main-sequence stars and the modest but significant shear of the modern-day Sun. Various explanations for the likely rigid rotation are considered. |
Keywords | stars: activity – stars: rotation – stars: solar-type – starspots |
ANZSRC Field of Research 2020 | 510109. Stellar astronomy and planetary systems |
Public Notes | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2019 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
Byline Affiliations | Centre for Astrophysics |
Mackenzie Presbyterian University, Brazil | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q5726/differential-rotation-of-kepler-71-via-transit-photometry-mapping-of-faculae-and-starspots
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