Estimating stellar rotation from starspot detection during planetary transits
Tipo
Artigo
Data de publicação
2008
Periódico
Astrophysical Journal
Citações (Scopus)
64
Autores
Silva-Valio A.
Orientador
Título da Revista
ISSN da Revista
Título de Volume
Membros da banca
Programa
Resumo
A new method for determining the stellar rotation period is proposed here, based on the detection of starspots during transits of an extrasolar planet orbiting its host star. As the planet eclipses the star, it may pass in front of a starspot which will then make itself known through small flux variations in the transit light curve. If we are lucky enough to catch the same spot on two consecutive transits, it is possible to estimate the stellar rotational period. This method is successfully tested on transit simulations on the Sun yielding the correct value for the solar period. By detecting two starspots on more than one transit of HD 209458 observed by the Hubble Space Telescope, it was possible to estimate a period of either 9.9 or 11.4 days for the star, depending on which spot is responsible for the signature in the light curve a few transits later. Comparison with period estimates of HD 209458 reported in the literature indicates that 11.4 days is the most likely stellar rotation period. © 2008. The American Astronomical Society. All rights reserved. Printed in U.S.A.