Numerical Modeling of Patchy Brown Dwarf Atmospheres 145 views

Brown dwarfs experience rotational variability caused by heterogeneous atmospheres with hot spots, cloud structure, and chemical composition variations. Interpreting observations requires understanding how these features project into disk-integrated signals and how that projection depends on both the atmospheric scale and inclination. In this study, we investigate these effects through three different avenues. A spherical harmonic analysis shows that variability is dominated by large-scale structure, with small-scale structure strongly weakened by disk integration. We then incorporate inclination by rotating atmospheric maps prior to radiative transfer calculations, showing that viewing angle modifies the observed flux. Finally, we examine the performance of Principal Component Analysis (PCA) on synthetic spectra generated from temperature and water abundance variations. We find that the first principal component primarily reflects overall flux changes, and the temperature- and water abundance-driven signals produce similar spectral signatures that are difficult to distinguish. These results show that different atmospheric processes can produce similar observational signals, making it difficult for PCA alone to isolate the true source of variability.

BS (Bachelor of Science)

Brown dwarfs; Atmospheric Variability; Principal Component Analysis; Inclination

English

2026-05-11