title: Equilibrium Chemistry in a Brown Dwarf's Atmosphere: Cesium in Gliese 229B.
abstract: The distribution of Cs in Gliese 229B's atmosphere reveals how equilibrium chemistry establishes the atmospheric composition. The rapid kinetics of cesium chemistry keeps the Cs abundance in thermochemical equilibrium and renders Cs a sensitive measure of chemical processes in brown dwarf atmospheres. Observations of Gliese 229B indicate a subsolar bulk abundance of Cs, the depletion of alkali metals in the upper atmosphere from condensation, and a partitioning of heavy elements different from that of the Sun.
authors.initials: CA
authors.lastname: Griffith
authors.initials: RV
authors.lastname: Yelle