Laboratoire d'Astrohpysique de l'Observatoire de Grenoble
414, rue de la Piscine, BP 53
SF2A- PNPS-
38041
Grenoble cedex9, France
Presentation 1 : Oral
Scattered Light models of young circumstellar disks (PNPS)
Francois Menard and Gaspard Duchene
We present scattered light models of the newly discovered disks associated to the T Tauri stars IRAS 04158+2805 and LkHa 263 C.
The observed intensity distribution is well matched by the models.
The results show that large grains are not needed to match
the observed scattered light distribution and that interstellar grains, as prescribed by Mathis and Whiffen for example, may be too forward throwing.
Models of the polarised scattered light of the disk of HK Tau/c
are also presented. A comparison of these models with 1mm and 3mm
IRAM Bure data and thermal emission models provides interesting constraints on our knowledge of the dust content of this disk.
Presentation 2 : Poster
Linear Polarimetry of Brown Dwarfs (PNPS)
Francois Menard, Xavier Delfosse and Jean-Louis Monin
The atmosphere of Brown Dwarfs become cool enough to allow dust particles to form as they age. There has been claims, for fast rotating brown dwarfs, that the dust could scatter light and produce a large linear polarisation.
In order to verify that claim we present the linear polarimetric measurements of 9 late-M and L-type dwarfs obtained with the VLT in December 2001 and May 2002. The 5 brown dwarfs observed in December
do not appear to have a detectable polarisation. Data reduction is under way for the remaining 4 object.