IALP   13078
INSTITUTO DE ASTROFISICA LA PLATA
Unidad Ejecutora - UE
artículos
Título:
Oligarchic planetesimal accretion and giant planet formation
Autor/es:
FORTIER, A. BENVENUTO, O. BRUNINI, A.
Revista:
ASTRONOMY AND ASTROPHYSICS
Editorial:
EDP Sciences
Referencias:
Año: 2007 vol. 473 p. 311 - 322
ISSN:
0004-6361
Resumen:
Aims. In the context of the core instability model, we present calculations of in situ giant planet formation. The oligarchic growthregime of solid protoplanets is the model adopted for the growth of the core. This growth regime for the core has not been consideredbefore in full evolutionary calculations of this kind.Methods. The full differential equations of giant planet formation were numerically solved with an adaptation of a Henyey-type code.The planetesimals accretion rate was coupled in a self-consistent way to the envelope’s evolution.Results. We performed several simulations for the formation of a Jupiter-like object by assuming various surface densities for theprotoplanetary disc and two different sizes for the accreted planetesimals. We first focus our study on the atmospheric gas drag thatthe incoming planetesimals suffer. We find that this effect gives rise to a major enhancement on the effective capture radius of theprotoplanet, thus leading to an average timescale reduction of ∼30%–55% and ultimately to an increase by a factor of 2 of the finalmass of solids accreted as compared to the situation in which drag effects are neglected. In addition, we also examine the importanceof the size of accreted planetesimals on the whole formation process. With regard to this second point, we find that for a swarm ofplanetesimals having a radius of 10 km, the formation time is a factor 2 to 3 shorter than that of planetesimals of 100 km, the factordepending on the surface density of the nebula. Moreover, planetesimal size does not seem to have a significant impact on the finalmass of the core.