Published online by Cambridge University Press: 10 November 2011
A close-in massive planet affects the angular momentum of its host star through tidal and magnetic interactions. The transiting planets allow us to study the distribution of the spin and orbital angular momenta in star-planet systems. Considering a sample of about 70 systems, we find that stars having an effective temperature between 6000 and 6700 K and a rotation period shorter than 10 days show a rotation synchronized with the orbit of their hot Jupiters or have a rotation period twice the orbital period of their planets. Such rotational behaviours cannot be explained on the basis of tidal interactions alone. Besides, the gyrochronology relationship for those systems holds if an angular momentum loss rate smaller by about 30 percent than in stars without hot Jupiters is assumed.