A&A 436, 363-372 (2005)
Orbital migration and the period distribution of exoplanetsA. Del Popolo1, 2, N. Ercan1 and I. S. Yesilyurt1 1
aziçi University, Physics Department,
80815 Bebek, Istanbul, Turkey
Dipartimento di Matematica, Università Statale di Bergamo,
via dei Caniana, 2, 24127, Bergamo, Italy
(Received 30 June 2004 / Accepted 24 December 2004)
We use the model for the migration of
planets introduced in Del Popolo et al. (2003, MNRAS, 339, 556)
to calculate the observed mass and semimajor axis distribution of extra-solar planets.
The assumption that the surface density in planetesimals is
proportional to that of gas is relaxed, and in order to describe disc evolution
we use a method
which, using a series of simplifying assumptions, is able
to simultaneously follow the evolution of gas and solid particles for
The distribution of planetesimals
is used to study the migration rate of
a giant planet through the model described in the present paper.
The disk and migration models are used to calculate the distribution
of planets as function of mass and semimajor axis. The results show that the
model can give a reasonable prediction of planets' semi-major axes and mass distribution.
In particular there is a pile-up of planets at
AU, a minimum near 0.3 AU,
indicating a paucity of planets at that distance, and a rise
for semi-major axes larger than 0.3 AU, out to 3 AU.
The semi-major axis distribution shows that the more massive planets (typically, masses larger
) form preferentially in the outer regions
and do not migrate much. Intermediate-mass objects migrate more easily
whatever the distance at which they form, and that the lighter planets (masses from sub-Saturnian to
Jovian) migrate easily.
planets and satellites: general --
planetary system --
planets and satellites: formation
© ESO 2005