Stephens, Denise C.

Contact Email: densteph@nmsu.edu
Institute: New Mexico State University
First Coauthor: Mark S. Marley
Institute: NASA Ames
Second Coauthor: Keith S. Noll
Institute: STScI
Presenting Thesis: Yes
Subject Area: Brown Dwarfs & Extrasolar Planets
Waveband: Infrared
Technique: Photometry
Presentation: Poster Display
Title: Near-Infrared Photometry of L and T Dwarfs
Abstract: During the past five years, the discovery of brown dwarfs has generated a renewed interest in the study and understanding of substellar mass objects and has led to the creation of two new spectral classes, L ( $\rm T_{eff}$$\approx$ 2000 K to 1300 K) and T (< 1300 K). To better understand and model the atmospheres of these objects, we've obtained K- and L-band photometry with the Keck I telescope for a representative sample of L and T dwarfs. These observations are motivated in part by the desire to understand the abundance of $\rm CH_{4}$ and $\rm H_{2}O$, particularly at the L to T transition where CO reacts with $\rm H_{2}$ to produce these molecules. We are also interested in how the presence of clouds in the latest L dwarfs may alter the emitted flux at certain wavelengths and in finding filters and spectral regions which are relatively insensitive to the presence of clouds and can provide reliable temperature scale information. With these goals in mind, we will present our most recent observations along with model predictions and discuss the trends we observe as a function of spectral type and what these trends tell us about the appearance of $\rm CH_{4}$ and the effect of clouds.