Name/Affiliation: Kevin Hardegree-Ullman (University of Toledo)
Photometric Variability of Y Dwarfs
Condensate clouds are present in brown dwarf atmospheres due to their low surface temperatures. Y dwarfs are the coolest (Teff < 600 K) class of brown dwarfs currently known and thus allow us to study the unique atmospheric physics that occur at these temperatures including the formation of sulfide, chloride, and water clouds. Dynamic inhomogeneities in cloud cover should manifest as photometric variabilities in the observed light curves of brown dwarfs, as shown by Morales-Calderón et al. (2006) in two brown dwarfs at 4.5 microns, and Heinze et al. (2013) in one brown dwarf at 3.6 microns. We will describe our ongoing program to monitor fourteen Y dwarfs for photometric variability at 3.6 and 4.5 microns with the Spitzer Space Telescope and present initial results including the first detection of Y dwarf variability.