A deeper view of the CoRoT-9 planetary system. A small non-zero eccentricity for CoRoT-9b likely generated by planet-planet scattering

Abstract : CoRoT-9b is one of the rare long-period (P=95.3 days) transiting giant planets with a measured mass known to date. We present a new analysis of the CoRoT-9 system based on five years of radial-velocity (RV) monitoring with HARPS and three new space-based transits observed with CoRoT and Spitzer. Combining our new data with already-published measurements we redetermine the CoRoT-9 system parameters and find good agreement with the published values. We uncover a higher significance for CoRoT-9b's small but non-zero eccentricity ($e=0.133^{+0.042}_{-0.037}$) and find no evidence for additional planets in the system. We use simulations of planet-planet scattering to show that CoRoT-9b's eccentricity may have been generated by an instability in which a $\sim 50~M_\oplus$ planet was ejected from the system. This scattering would not have produced a spin-orbit misalignment, so we predict that CoRoT-9b's orbit should lie within a few degrees of the initial plane of the protoplanetary disk. As a consequence, any significant stellar obliquity would indicate that the disk was primordially tilted.
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Astronomy and Astrophysics - A&A, EDP Sciences, 2017, 603, pp.id.A43. <10.1051/0004-6361/201730624>
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https://hal.archives-ouvertes.fr/hal-01493751
Contributeur : Marie-Paule Pomies <>
Soumis le : mercredi 22 mars 2017 - 08:45:07
Dernière modification le : mardi 11 juillet 2017 - 01:12:08

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A. S. Bonomo, G. Hébrard, Sean N. Raymond, F. Bouchy, A. Lecavelier Des Etangs, et al.. A deeper view of the CoRoT-9 planetary system. A small non-zero eccentricity for CoRoT-9b likely generated by planet-planet scattering. Astronomy and Astrophysics - A&A, EDP Sciences, 2017, 603, pp.id.A43. <10.1051/0004-6361/201730624>. <hal-01493751>

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