F. Marzari, C. Baruteau, H. Scholl, P. Thebault
Discs in binaries have a complex behavior because of the perturbations of the
companion star. Planet formation in binary-star systems both depend on the
companion star parameters and on the properties of the circumstellar disc. An
eccentric disc may increase the impact velocity of planetesimals and therefore
jeopardize the accumulation process. We model the evolution of discs in close
binaries including the effects of self-gravity and adopting different
prescriptions to model the disc's radiative properties. We focus on the
dynamical properties and evolutionary tracks of the discs. We use the
hydrodynamical code FARGO and we include in the energy equation heating and
cooling effects. Radiative discs have a lower disc eccentricity compared to
locally isothermal discs with same temperature profile. As a consequence, we do
not observe the formation of an internal elliptical low density region as in
locally isothermal disc models. However, the disc eccentricity depends on the
disc mass through the opacities. Akin to locally isothermal disc models,
self-gravity forces the disc's longitude of pericenter to librate about a fixed
orientation with respect to the binary apsidal line ($\pi$). The disc's
radiative properties play an important role in the evolution of discs in
binaries. A radiative disc has an overall shape and internal structure that are
significantly different compared to a locally isothermal disc with same
temperature profile. This is an important finding both for describing the
evolutionary track of the disc during its progressive mass loss, and for planet
formation since the internal structure of the disc is relevant for
planetesimals growth in binary systems. The non-symmetrical distribution of
mass in these discs causes large eccentricities for planetesimals that may
affect their growth.
View original:
http://arxiv.org/abs/1201.2293
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