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

CORREA OTTO, J., MICHTCHENKO, T. ; BEAUGE, C.

ASTRONOMY AND ASTROPHYSICS

EDP SCIENCES S A

Lugar: Paris; Año: 2013 vol. 560 p. 1 - 10

0004-6361

We revise the model for the origin of the HD 45364 exoplanetary system proposed by Rein et al. (2010, A&A, 510, A4), which iscurrently known to host two planets close to the 3/2 mean-motion resonance (MMR). We show that due to the high surface densityof the protoplanetary disk needed for type III migration, this model can only lead to planets in a quasi-resonant regime of motionand thus is not consistent with the resonant configuration obtained by Correia et al. (2009, A&A, 496, 521). Although both resonantand quasi-resonant solutions are statistically indistinguishable with respect to radial velocity measurements, their distinct dynamicalbehavior is intriguing. We used the semi-analytical model to confirm the quantitative difference between two configurations. To forma system that evolves inside the 3/2 resonance, we developed 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 evolutionary path was chosendue to a detailed analysis of the phase space structure in the vicinity of the 3/2 MMR that employed dynamical mapping techniques.The outcomesd of our simulations are able to very closely reproduce the 3/2 resonant dynamics obtained from the best fit presented byCorreia et al. In addition, by varying the strength of the eccentricity damping, we can also simulate the quasi-resonant configurationsimilar to that reported in Rein et al. We furthermore show that our scenario is reliable with respect to the physical parameters involvedin the resonance-trapping process. However, our scenario can only be confirmed with additional radial velocities measurements.