Gelino, Christopher

Contact Email: crom@nmsu.edu
Institute: Department of Astronomy
New Mexico State University
First Coauthor: Mark Marley
Institute: New Mexico State University, NASA/AMES
Second Coauthor: Jon Holtzman
Institute: New Mexico State University
Presenting Thesis: Yes
Subject Area: Brown Dwarfs & Extrasolar Planets
Waveband: Optical
Technique: Photometry
Presentation: Poster Display
Title: A case for clouds in L dwarfs
Abstract: The effective temperatures of L dwarfs span the range where molecules can condense to form clouds in their atmospheres. In fact, clouds are required for spectra of model atmospheres to fit the observed spectra. As on Jupiter, clouds on these objects need not be uniform. Non-uniform cloud features can provide a source of photometric variations in much the same way that non-uniform starspot coverage can cause variations in hotter objects. Photometric variations have already been reported for several L dwarfs by Bailer-Jones & Mundt (2001). We present results of our own variability search that includes observations of some objects over four continuous months. We also find photometric variability among the L-dwarfs and will discuss the characteristics of the variable objects, comment on the longevity of surface features, and argue that magnetic effects are not responsible for the observed variability.