Stability of resonant configurations during the migration of planets and constraints on disk-planet interactions
Authors:
Delisle et al
Abstract:
We study the stability of mean-motion resonances (MMR) between two planets during their migration in a protoplanetary disk. We use an analytical model of resonances, and describe the effect of the disk by a migration timescale (T_{m,i}) and an eccentricity damping timescale (T_{e,i}) for each planet (i=1,2 respectively for the inner and outer planet). We show that the resonant configuration is stable if T_{e,1}/T_{e,2} > (e_1/e_2)^2. This general result can be used to put constraints on specific models of disk-planet interactions. For instance, using classical prescriptions for type I migration, we show that when the angular momentum deficit (AMD) of the inner orbit is larger than the outer's orbit AMD, resonant systems must have a locally inverted disk density profile to stay locked in resonance during the migration. This inversion is very untypical of type I migration and our criterion can thus provide an evidence against classical type I migration. That is indeed the case for the Jupiter-mass resonant systems HD 60532b, c (3:1 MMR), GJ 876b, c (2:1 MMR), and HD 45364b, c (3:2 MMR). This result may be an evidence for type II migration (gap opening planets), which is compatible with the large masses of these planets.
Tuesday, July 7, 2015
Stability of Resonant Configurations During the Migration of Exoplanets
Labels:
exoplanet migration,
gj 876,
gj 876b,
GJ 876c,
HD 45364,
HD 45364b,
HD 45364c,
HD 60532,
HD 60532b,
HD 60532c,
orbital mechanics,
orbital resonances
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