Photospheric activity and rotation of the planet-hosting star CoRoT-4a

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Photospheric activity and rotation of the planet-hosting star CoRoT-4a

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dc.contributor.author Lanza, A. F. en_GB
dc.contributor.author Aigrain, Suzanne en_GB
dc.contributor.author Messina, S. en_GB
dc.contributor.author Leto, G. en_GB
dc.contributor.author Pagano, I. en_GB
dc.contributor.author Auvergne, M. en_GB
dc.contributor.author Baglin, A. en_GB
dc.contributor.author Barge, P. en_GB
dc.contributor.author Bonomo, A. S. en_GB
dc.contributor.author Collier Cameron, A. en_GB
dc.contributor.author Cutispoto, G. en_GB
dc.contributor.author Deleuil, M. en_GB
dc.contributor.author De Medeiros, J. R. en_GB
dc.contributor.author Foing, B. en_GB
dc.contributor.author Moutou, C. en_GB
dc.date.accessioned 2009-12-03T15:33:08Z en_GB
dc.date.accessioned 2011-01-25T11:54:10Z en_US
dc.date.accessioned 2013-03-20T13:15:38Z
dc.date.issued 2009 en_GB
dc.description.abstract Aims. The space experiment CoRoT has recently detected a transiting hot Jupiter in orbit around a moderately active F-type mainsequence star (CoRoT-4a). This planetary system is of particular interest because it has an orbital period of 9.202 days, the second longest one among the transiting planets known to date. We study the surface rotation and the activity of the host star during an uninterrupted sequence of optical observations of 58 days. Methods. Our approach is based on a maximum entropy spot modelling technique extensively tested by modelling the variation in the total solar irradiance. It has been successfully applied to model the light curve of another active star with a transiting planet observed by CoRoT, i.e., CoRoT-2a. It assumes that stellar active regions consist of cool spots and bright faculae, analogous to sunspots and solar photospheric faculae, whose visibility is modulated by stellar rotation. Results. The modelling of the light curve of CoRoT-4a reveals three main active longitudes with lifetimes between ˜30 and ˜60 days that rotate quasi-synchronously with the orbital motion of the planet. The different rotation rates of the active longitudes are interpreted in terms of surface differential rotation, and a lower limit of 0.057 ± 0.015 is derived for its relative amplitude. The enhancement of activity observed close to the subplanetary longitude suggests a magnetic star-planet interaction, although the short duration of the time series prevents us from drawing definite conclusions. Conclusions. The present work confirms the quasi-synchronicity between stellar rotation and planetary orbital motion in the CoRoT-4 system and provides a lower limit for the surface differential rotation of the star. This information can be important in trying to understand the formation and evolution of this highly interesting planetary system. Moreover, there is an indication of a possible star-planet magnetic interaction that needs to be confirmed by future studies. en_GB
dc.identifier.citation 506 (1), pp. 255-262 en_GB
dc.identifier.doi 10.1051/0004-6361/200811487 en_GB
dc.identifier.uri http://hdl.handle.net/10036/87333 en_GB
dc.language.iso en en_GB
dc.publisher EDP Sciences en_GB
dc.relation.url http://dx.doi.org/10.1051/0004-6361/200811487 en_GB
dc.subject stars: magnetic fields en_GB
dc.subject stars: late-type en_GB
dc.subject stars: activity en_GB
dc.subject stars: rotation en_GB
dc.subject planetary systems en_GB
dc.title Photospheric activity and rotation of the planet-hosting star CoRoT-4a en_GB
dc.type Article en_GB
dc.date.available 2009-12-03T15:33:08Z en_GB
dc.date.available 2011-01-25T11:54:10Z en_US
dc.date.available 2013-03-20T13:15:38Z
dc.identifier.issn 0004-6361 en_GB
dc.identifier.issn 1432-0746 en_GB
dc.description Copyright © The European Southern Observatory (ESO) en_GB
dc.identifier.journal Astronomy and Astrophysics en_GB


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