Cool Stars 14 - Submitted Abstract # 213
This version created on 05 October 2006

Outstanding Issues in Our Understanding of L and T Dwarfs


J. Davy Kirkpatrick, IPAC/Caltech

Since the discovery of the first L dwarf 18 years ago and the
discovery of the first T dwarf 7 years thereafter, we have come to
understand a great deal about objects cooler than spectral type M.
Still, a number of important issues remain to be resolved.  In this
talk I will discuss three that I regard as the most thought-provoking
and address the following questions on each:  
     (1) What role do gravity and metallicity play in shaping
     the emergent spectra of L and T dwarfs?  Can we establish a
     robust classification scheme for dwarfs of unusual log(g)
     or [M/H] so that such objects are easily characterized?
     What are the benefits of classifying on such a scheme?  
     (2) What physical processes are driving the unusual
     behavior at the transition between L dwarfs and T dwarfs? 
     What role do binaries play?  What observations can we take
     to test theories regarding this transition?
     (3) What might objects cooler than T8 look like?  Which
     upcoming surveys are best suited to uncovering them?  How
     will we know a Y dwarf when we first observe one?  
This review talk will also highlight the many other brown dwarf
related talks and posters addressing these issues, and in doing
so will attempt to place these research results in context for
Cool Stars participants.

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