NIR light curve of 2MASS J00501994-3322402

Only a handful of late T brown dwarfs have been monitored for spectrophotometric variability, leaving incomplete the study of the atmospheric cloud structures of the coldest brown dwarfs, which share temperatures with some cold, directly imaged exoplanets. 2MASS J00501994-332240 is a T7.0 rapidly rotating, field brown dwarf that showed low-level photometric variability in data obtained with the Spitzer Space Telescope.

We monitored 2MASS J00501994-332240 during ~2.6hr with MOSFIRE, installed at the Keck I telescope, with the aim of constraining its near-infrared spectrophotometric variability. We measured fluctuations with a peak-to-peak amplitude of 1.48%{+/-}0.75% in the J-band photometric light curve, an amplitude of 0.62%{+/-}0.18% in the J-band spectrophotometric light curve, an amplitude of 1.26%{+/-}0.93% in the H-band light curve, and an amplitude of 5.33%{+/-}2.02% in the CH4-H2O band light curve.