Burgasser, Adam

Contact Email: diver@its.caltech.edu
Institute: Caltech Physics 103-33 Pasadena, CA 91125
Research URL:http://www.its.caltech.edu/~diver/homepage/research/tdwarf.html
Presenting Thesis: Yes
Subject Area: Brown Dwarfs & Extrasolar Planets
Waveband: Infrared
Technique: Spectroscopy
Presentation: Oral Contribution: Tuesday
Title: The Classification of T dwarfs
Abstract: The recent discovery of objects cooler than M9 V has prompted the definition of two new spectroscopic classes, L and T, which are extensions of the main sequence into the brown dwarf regime. In this talk, I discuss a classification scheme for T dwarfs, brown dwarfs that show spectroscopic features of methane in the near-infrared. This scheme is based on near-infrared data, the spectral region where these objects are brightest, and is tied to dominant features of methane, water, and collision-induced H2 absorption. I show that there is a smooth continuum of spectral morphology from the latest M dwarfs through the T dwarfs, and present a recipe for classification based on spectral indices. I then show how our scheme coincides quite closely with that developed by Geballe et al., better than +/- 0.5 subclasses, and discuss the underlying physical causes of the observed spectral sequence. Education: Graduate