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arXiv · 1007.3647

Photospheric activity, rotation, and star-planet interaction of the planet-hosting star CoRoT-6

A. F. Lanza·A. S. Bonomo·I. Pagano·G. Leto·S. Messina·G. Cutispoto·C. Moutou·S. Aigrain·R. Alonso·P. Barge·M. Deleuil·M. Fridlund·A. Silva-Valio·M. Auvergne·A. Baglin·A. Collier Cameron
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Abstract

The CoRoT satellite has recently discovered a hot Jupiter that transits across the disc of a F9V star called CoRoT-6 with a period of 8.886 days. We model the photospheric activity of the star and use the maps of the active regions to study stellar differential rotation and the star-planet interaction. We apply a maximum entropy spot model to fit the optical modulation as observed by CoRoT during a uninterrupted interval of about 140 days. Photospheric active regions are assumed to consist of spots and faculae in a fixed proportion with solar-like contrasts. Individual active regions have lifetimes up to 30-40 days. Most of them form and decay within five active longitudes whose different migration rates are attributed to the stellar differential rotation for which a lower limit of \Delta \Omega / \Omega = 0.12 \pm 0.02 is obtained. Several active regions show a maximum of activity at a longitude lagging the subplanetary point by about 200 degrees with the probability of a chance occurrence being smaller than 1 percent. Our spot modelling indicates that the photospheric activity of CoRoT-6 could be partially modulated by some kind of star-planet magnetic interaction, while an interaction related to tides is highly unlikely because of the weakness of the tidal force.

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A. F. Lanza, A. S. Bonomo, I. Pagano, G. Leto, S. Messina, G. Cutispoto, C. Moutou, S. Aigrain, R. Alonso, P. Barge, M. Deleuil, M. Fridlund, A. Silva-Valio, M. Auvergne, A. Baglin, A. Collier Cameron. 2010-07-21. Photospheric activity, rotation, and star-planet interaction of the planet-hosting star CoRoT-6. https://doi.org/10.1051/0004-6361/201015245

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