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Post Info TOPIC: CoRoT-11


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Posts: 131433
Date:
CoRoT-11b
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Title: Doppler tomography of transiting exoplanets: A prograde, low-inclined orbit for the hot Jupiter CoRoT-11b
Authors: Davide Gandolfi, Andrew Collier Cameron, Michael Endl, Antonino F. Lanza, Cilia Damiani, Roi Alonso, William D. Cochran, Magali Deleuil, Malcolm Fridlund, Artie P. Hatzes, Eike W. Guenther

We report the detection of the Doppler shadow of the transiting hot Jupiter CoRoT-11b. Our analysis is based on line-profile tomography of time-series, Keck/HIRES high-resolution spectra acquired during the transit of the planet. We measured a sky-projected, spin-orbit angle of 0.1 2.6 degrees, which is consistent with a very low-inclined orbit with respect to the stellar rotation axis. We refined the physical parameters of the system using a Markov chain Monte Carlo simultaneous fitting of the available photometric and spectroscopic data. An analysis of the tidal evolution of the system shows how the currently measured obliquity and its uncertainty translate into an initial absolute value of less than about 10 degrees on the zero-age main sequence, for an expected average modified tidal quality factor of the star Q'* > 4 x 10^6. This is indicative of an inward migration scenario that would not have perturbed the primordial low obliquity of CoRoT-11b. Taking into account the effective temperature and mass of the planet host star (Teff=6440 K, M*=1.23 solar masses), the system can be considered a new telling exception to the recently proposed trend, according to which relatively hot and massive stars (Teff>6250 K, M*>1.2 solar masses) seem to be preferentially orbited by hot Jupiters with high obliquity.

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Posts: 131433
Date:
CoRoT-11
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Title: Constraining tidal dissipation in F-type main-sequence stars: the case of CoRoT-11
Authors: A. F. Lanza, C. Damiani, D. Gandolfi

Tidal dissipation in late-type stars is presently poorly understood and the study of planetary systems hosting hot Jupiters can provide new observational constraints to test proposed theories. We focus on systems with F-type main-sequence stars and find that the recently discovered system CoRoT-11 is presently the best suited for such a kind of investigation. A classic constant tidal lag model is applied to reproduce the evolution of the system from a plausible nearly synchronous state on the ZAMS to the present state, thus putting constraints on the average modified tidal quality factor <Q'_s> of its F6V star. It is found that <Q'_s> is approximately between 2.5E+06 and 1.7E+07 with an uncertainty related to the constant tidal lag hypothesis within a factor of about 2. Moreover, we discuss how the present value of Q'_s can be measured by a timing of the mid-epoch and duration of the transits as well as of the planetary eclipses to be observed in the infrared with an accuracy of about 0.5-1 s over a time baseline of about 25 yr. CoRoT-11 is an highly interesting system potentially allowing us a direct measure of the tidal dissipation in an F-type star as well as the detection of the precession of the orbital plane of the planet that provides us with an accurate upper limit for the obliquity of the stellar equator. If the planetary orbit has a significant eccentricity (e>0.05), it will be possible to detect also the precession of the line of the apsides and derive information on the Love number of the planet and its tidal quality factor.

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