Bibcode
Leggett, S.; Freedman, R.; Geballe, T.; Golimowski, D.; Lodieu, N.; Marley, M.; Pinfield, D.; Saumon, D.; Stephens, D.; Warren, S.
Bibliographical reference
14th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun ASP Conference Series, Vol. 384, proceedings of the conference held 5-10 November, 2006, at the Spitzer Science Center and Michelson Science Center, Pasadena, California, USA. Edited by Gerard van Belle., p.98
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4
2008
Citations
0
Refereed citations
0
Description
Eleven years after the discovery of the first T dwarf, a population of
ultracool L and T dwarfs has been identified that is large enough to
show a range of atmospheric properties. Also, model atmospheres are
sufficiently advanced to study these properties in detail. Since the
last Cool Stars meeting, several observational developments have aided
in these studies. We present recent mid-infrared photometry and
spectroscopy from the Spitzer Space Telescope which confirms the
prevalence of vertical mixing in the atmospheres of L and T dwarfs.
Hence, the 700~K to 2200~K L and T dwarf photospheres require several
parameters for successful modelling: effective temperature, gravity,
metallicity, grain sedimentation efficiency and vertical mixing
efficiency. We also describe initial results of a search for ultracool
dwarfs in the UKIRT Infrared Deep Sky Survey, and present the latest T
dwarf found to date. We conclude with a discussion of the possible
spectral indicators of Y dwarfs.