[Previous] | [Session 18] | [Next]

[18.13] Collisional dust production in extrasolar discs: a new dynamical and photometric model

P. Thebault (Observatoire de Meudon), J.-C. Augereau (Leiden Observatory)

In most extrasolar discs, the observed dust is believed to be produced by collisional cascades starting at (at least) kilometre-sized planetesimals. The numerical studies of Thebault et al. (A&A 2003) have shown on a peculiar example, the inner Beta-Pictoris disc, that the collisional size distribution from micron-sized grains to planetesimals might significantly depart from the classical dN \alpha r^-3.5dr power law. The main reason for this departure is the specific behaviour of the smallest grains, i.e. stellar radiation blow-out size limit and highly eccentric orbits, which indirectly affects the whole size distribution.

We extend our approach to the more general case of any collisionaly produced dust disc. We consider mutualy interacting concentric annuli with a collisionaly evolving size distribution ranging from the blow-out size to 50 km objects. Realistic grain optical properties are taken into account in order to derive scattered light and thermal images. Complete S.E.D. profiles are also derived and compared to observational data. Preliminary results are presented for the \beta-Pic system and for other well known discs.

The author(s) of this abstract have provided an email address for comments about the abstract: philippe.thebault@obspm.fr

[Previous] | [Session 18] | [Next]

Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.