Clouds, Brightening and Multiplicity Across theL Dwarf/T Dwarf Transition

摘要

The transition between the two lowest-luminosity spectral classes of brown dwarfs—theL dwarfs and T dwarfs—is traversed by nearly all brown dwarfs as they cool over time. Yet distinctfeatures of this transition, such as the "J-band bump" and an unusually high rate of multiplicity,remain outstanding problems, although evidence points to condensate cloud evolution as a criticalcomponent. Using a Monte Carlo population simulation that incorporates the empirical spectralproperties of unresolved brown dwarfs in magnitude-limited samples, I demonstrate that the J-band bump and enhanced multiplicity naturally emerge from a short timescale of photosphericcloud dissipation. This timescale may help constrain future evolutionary models exploring the clouddissipation process.