Planetary migration and (near)-resonant capture of TRAPPIST-1 planets

CAROLINA CHARALAMBOUS; CRISTIAN BEAUGE

Liege

Conferencia; TRAPPIST-1 Conference; 2019

Liege Universite

The observed offset of the TRAPPIST-1 near resonant population is muchhigher than expected. A way to explain the position of the planets far apart from resonance is usually by tidal efects (Lee et al., 2013; Papaloizou et al., 2015; Delisle et al., 2014) or by interaction with the protoplanetary disk (Chatterjee & Ford, 2015). This means that first the capture occurs, and then the escape takes place. Through type-I migration it is possible to get systems trapped in different commensurabilities. Migration rates depend on the density of the gas-disk, the mass of the migrating planets, semimajor axis and eccentricities, among others. The main problem for understanding the dynamical evolution of this system is that the masses of the planets are estimated with great uncertaintiesimplying that we can not delimit the migration rates. In this work we perform a Monte Carlo analysis in order to put some constraints in the values of the masses, within the limits of the observational data. As presented in Charalambous et al. (2018), we use the dynamical maps for fictitious three-planet systems which expose the dynamical structure involving two or three planets and also indicate possible migration routes to pure three-planet commensurabilities. By N-body simulations of type-I migration we search the final orbital configuration compared with present-day values of the resonance offsets, without imposing an ad-hoc tidal dissipation. We were able to reproduce all three-planet sub-systemslocations, except for one: the inner triplet of planets b-c-d.