Tuesday, July 9, 2013

1307.1822 (J. A. Correa-Otto et al.)

A new scenario for the origin of the 3/2 resonant system HD45364    [PDF]

J. A. Correa-Otto, T. A. Michtchenko, C. Beaugé
In this paper we revise the model proposed by Rein et al. (2010) for the origin of the HD45364 exoplanetary system, currently known to host two planets close to the 3/2 mean-motion commensurability (MMR). We show that, due to high surface density of the protoplanetary disk needed for Type III migration, this model could only lead to planets in a quasi-resonant regime of motion, and thus not consistent with the resonant configuration obtained by Correia et al. (2009). Although both solutions are statistically indistinguishable with respect to radial velocity measurements, their distinct dynamical behaviour is intriguing. In order to form a system evolving inside the 3/2 resonance, we develop a different model. Our scenario includes an interaction between different (but slower) planetary migration types, planet growth, and gap formation in the protoplanetary disk. The choice of the described evolutionary path was due to a detailed analysis of the structure of the phase space in the vicinity of the 3/2 MMR employing a semi-analytical Hamiltonian model. The outcomes of our simulations are able to reproduce very closely the 3/2 resonant dynamics obtained from the best-fit presented by Correia et al. (2009). Not only do our findings confirm the resonant nature of our solution, but also confirm that it is robust in the range of the typical values of the physical parameters involved in the resonance trapping process.
View original: http://arxiv.org/abs/1307.1822

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