Weather on Other Worlds IV: In-Depth Study of Photometric Variability and Radiative Timescales for Atmospheric Evolution in Four L Dwarfs

Rotational phase mapping of brown dwarfs allows exploration of different cloud and photospheric properties within the same atmospheres, allowing a separation of these parameters from global parameters, such as composition, surface gravity, and age. This work presents an in-depth characterization of high SNR light curves from the Spitzer Space Telescope with up to 13 hours of continuous monitoring of four dwarfs spanning the L3 to L8 spectral type. An exhaustive exploration of currently available state-of-the-art models explains the observed color changes for two of these dwarfs with a linear combination of two model cloudy surfaces differing in effective temperature, cloud opacity and vertical mixing. Using state-of-the-art purely radiative convective atmospheric models, we calculate basic radiative timescales for temperature perturbations in the atmosphere, and consider the effects of dynamics on these timescales. Along with dynamical atmospheric advection timescales, we discuss the relationships between model timescales and the observed light curve evolution