A&A 461, 1195-1208 (2007)
DOI: 10.1051/0004-6361:20066171
On the formation of terrestrial planets in hot-Jupiter systems
M. J. Fogg and R. P. NelsonAstronomy Unit, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
e-mail: [M.J.Fogg;R.P.Nelson]@qmul.ac.uk
(Received 3 August 2006 / Accepted 9 October 2006)
Abstract
Context.There are numerous extrasolar giant planets which orbit
close to their central stars. These "hot-Jupiters" probably
formed in the outer, cooler regions of their
protoplanetary disks, and migrated inward to
0.1 AU.
Since these giant planets must
have migrated through their inner systems at an early time, it is
uncertain whether they could have formed or retained terrestrial
planets.
Aims.We present a series of calculations aimed at examining
how an inner system of planetesimals/protoplanets,
undergoing terrestrial planet formation, evolves under the
influence of a giant planet undergoing inward type II migration
through the region bounded between 5-0.1 AU.
Methods.We have previously simulated the effect of gas giant planet
migration on an inner system protoplanet/planetesimal disk using a
N-body code which included gas drag and a prescribed
migration rate. We update our calculations here with an
improved model that incorporates a viscously evolving gas disk,
annular gap and inner-cavity formation due to the gravitational
field of the giant planet, and self-consistent evolution of the giant's
orbit.
Results.We find that
60% of the solids disk survives by being
scattered by the giant planet into external orbits. Planetesimals
are scattered outward almost as efficiently as protoplanets,
resulting in the regeneration of a solids disk where dynamical
friction is strong and terrestrial planet formation is able to
resume. A simulation that was extended for a few Myr after the
migration of the giant planet halted at 0.1 AU, resulted in an
apparently stable planet of
2
forming in the
habitable zone. Migration-induced mixing of volatile-rich material
from beyond the "snowline" into the inner disk regions means that
terrestrial planets that form there are likely to be water-rich.
Conclusions.We predict that hot-Jupiter systems are likely to harbor
water-abundant terrestrial planets in their habitable zones. These
planets may be detected by future planet search missions.
Key words: planets and satellites: formation -- methods: N-body simulations -- astrobiology
© ESO 2007

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