IALP   13078
INSTITUTO DE ASTROFISICA LA PLATA
Unidad Ejecutora - UE
artículos
Título:
The effects of ablation on the cross section of planetary envelopes at capturing planetesimals
Autor/es:
BENVENUTO, OMAR G.; BRUNINI, ADRIÁN
Revista:
ICARUS
Referencias:
Año: 2008 vol. 195 p. 882 - 894
ISSN:
0019-1035
Resumen:
We explore the cross section of giant planet envelopes at capturing
planetesimals of different sizes. For this purpose we employ two sets of
realistic planetary envelope models (computed assuming for the
protoplanetary nebula masses of 10 and 5 times the mass of the minimum
mass solar nebula), account for drag and ablation effects and study the
trajectories along which planetesimals move. The core accretion of these
models has been computed in the oligarchic growth regime [Fortier, A.,
Benvenuto, O.G., Brunini, A., 2007. Astron. Astrophys. 473,
311322], which has also been considered for the velocities of the
incoming planetesimals. This regime predicts velocities larger that
those used in previous studies of this problem. As the rate of ablation
is dependent on the third power of velocity, ablation is more important
in the oligarchic growth regime. We compute energy and mass deposition,
fractional ablated masses and the total cross section of planets for a
wide range of values of the critical parameter of ablation. In computing
the total cross section of the planet we have included the contributions
due to mass deposited by planetesimals moving along unbound orbits. Our
results indicate that, for the case of small planetary cores and low
velocities for the incoming planetesimals, ablation has a negligible
impact on the capture cross section in agreement with the results
presented in Inaba and Ikoma [Inaba, S., Ikoma, M., 2003. Astron.
Astrophys. 410, 711723]. However for the case of larger cores and
high velocities of the incoming planetesimals as predicted by the
oligarchic growth regime, we find that ablation is important in
determining the planetary cross section, being several times larger than
the value corresponding ignoring ablation. This is so regardless of the
size of the incoming planetesimals.