Clouds, Brightening and Multiplicity Across the L Dwarf/T Dwarf Transition

TL;DR

This paper uses population simulations to show that the J-band brightening and high multiplicity rates in brown dwarf transitions are due to rapid cloud dissipation, providing insights into their evolution.

Contribution

It introduces a Monte Carlo simulation model that links cloud dissipation timescales to observed spectral features and multiplicity in brown dwarfs.

Findings

J-band bump explained by cloud dissipation

High multiplicity linked to rapid cloud clearing

Simulation constrains cloud dissipation timescale

Abstract

The transition between the two lowest-luminosity spectral classes of brown dwarfs--the L dwarfs and T dwarfs--is traversed by nearly all brown dwarfs as they cool over time. Yet distinct features 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 critical component. Using a Monte Carlo population simulation that incorporates the empirical spectral properties 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 photospheric cloud dissipation. This timescale may help constrain future evolutionary models exploring the cloud dissipation process.