Space instrumentation

Abstract:

We report the results of observations designed to investigate the spectroscopic signatures of dust clouds on the L2 brown dwarf Kelu-1. Time-resolved medium-resolution spectra show no significant evidence of variability in the dust-sensitive TiO, CrH and FeH bandheads on a time-scale of 1-24 h. We do, however, report periodic variability in the pseudo-equivalent width of Hα consistent with the 1.8-h rotation period previously reported for this object. Near-contemporaneous I-band photometry shows evidence for non-periodic variability at the level of 2 per cent.