Astronomy and Astrophysics – Astronomy
Scientific paper
May 2007
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007aas...210.6905h&link_type=abstract
American Astronomical Society Meeting 210, #69.05; Bulletin of the American Astronomical Society, Vol. 39, p.177
Astronomy and Astrophysics
Astronomy
Scientific paper
T dwarfs are characterised by cool atmospheres that are depleted from dust and thus transparent to large optical depths. This was already evidenced by the hallmark methane absorption bands seen in the prototype of this class, Gliese 229B and has found further confirmation by the observation that the transition from the L to T spectral class is mainly associated with the removal of dust from the visible photosphere over a very small range in effective temperature. Successful modelling of T dwarf atmospheres therefore requires a correct description of the vertical distribution of condensates and of the changes in chemistry associated with the removal of condensible species. In addition line strengths and line profiles of molecular and atomic absorbers, in particular the alkali resonance lines, are required over a wide range in pressure and temperature.
The current status of theoretical models from the PHOENIX BT-Settl grid is presented and effects of gravity and metallicity on spectral characteristics compared. Rather small differences in chemical composition can produce significant changes in the spectral energy distribution, indicating that the vast majority of known T dwarfs have metallicities very close to solar.
Models of the coolest atmospheres predict that the spectral appearance of the yet to be detected Y dwarfs will depend strongly on the depletion of alkali metals and their line shapes at large depths.
No associations
LandOfFree
Models of T and Y Dwarfs does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Models of T and Y Dwarfs, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Models of T and Y Dwarfs will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1031425