We propose to use the unique capabilities offered by ISO to obtain
a low resolution mid-infrared spectrum of the newly discovered brown
dwarf candidate DENIS-P J0205-1159 (1).
Old brown dwarfs, like this new isolated objects, have cooled to sufficiently
low temperatures that dust forms in their atmospheres (Allard 1997, Tenerife BD
conference). Their atmospheric structure is still poorly understood. It is thus
essential that the atmospheric models can be constrained by observed energy
distributions, and especially important is the SED in the mid-IR where
continuum blanketing by dust will occur, and where a significant fraction
of the energy is emitted. Spectroscopy of one Brown Dwarf would
test the models and lead to a better understanding of Brown Dwarf atmospheres.
We have recently imaged DENIS-P J0205-1159 with ISOCAM and broad band
filters. We find its flux is sufficient to measure its spectrum with
the CAM-LW CVF. This is the LAST opportunity to measure the low resolution
spectrum of a brown dwarf before many years, ie. before SIRTF.
(1) Delfosse et al., Astronomy and Astrophysics, 327, L25;
Martin et al., Astronomy and Astrophysics 327, L29;
Tinney et al., Astrophysical Journal Letter 490, L95;