Lefèvre, Maxence; Tan, Xianyu; Lee, Elspeth K. H.; Pierrehumbert, R. T. (2022). Cloud-convection Feedback in Brown Dwarf Atmospheres. Astrophysical journal, 929(2), p. 153. Institute of Physics Publishing IOP 10.3847/1538-4357/ac5e2d
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Numerous observational evidence has suggested the presence of active meteorology in the atmospheres of brown dwarfs. A near-infrared brightness variability has been observed. Clouds have a major role in shaping the thermal structure and spectral properties of these atmospheres. The mechanism of such variability is still unclear, and neither 1D nor global circulation models can fully study this topic due to resolution. In this study, a convective-resolving model is coupled to gray-band radiative transfer in order to study the coupling between the convective atmosphere and the variability of clouds over a large temperature range with a domain of several hundred kilometers. Six types of clouds are considered, with microphysics including settling. The clouds are radiatively active through the Rosseland mean coefficient. Radiative cloud feedback can drive spontaneous atmospheric variability in both temperature and cloud structure, as modeled for the first time in three dimensions. Silicate clouds have the most effect on the thermal structure with the generation of a secondary convective layer in some cases, depending on the assumed particle size. Iron and aluminum clouds also have a substantial impact on the atmosphere. Thermal spectra were computed, and we find the strongest effect of the clouds is the smoothing of spectral features at optical wavelengths. Compared to observed L and T dwarfs on the color–magnitude diagram, the simulated atmospheres are redder for most of the cases. Simulations with the presence of cloud holes are closer to observations.
Item Type: |
Journal Article (Original Article) |
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Division/Institute: |
08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences 08 Faculty of Science > Physics Institute 10 Strategic Research Centers > Center for Space and Habitability (CSH) 08 Faculty of Science > Physics Institute > NCCR PlanetS |
UniBE Contributor: |
Lee, Elspeth |
Subjects: |
500 Science > 520 Astronomy 500 Science 500 Science > 530 Physics |
ISSN: |
0004-637X |
Publisher: |
Institute of Physics Publishing IOP |
Language: |
English |
Submitter: |
Danielle Zemp |
Date Deposited: |
16 Mar 2023 11:27 |
Last Modified: |
16 Mar 2023 23:27 |
Publisher DOI: |
10.3847/1538-4357/ac5e2d |
BORIS DOI: |
10.48350/180142 |
URI: |
https://boris.unibe.ch/id/eprint/180142 |
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