Univ. of Arizona, Tucson, AZ (United States). Lunar and Planetary Lab.
Univ. of Arizona, Tucson, AZ (United States). Lunar and Planetary Lab.; Univ. of Arizona, Tucson, AZ (United States). Steward Observatory; NASA Ames Research Center (ARC), Moffett Field, Mountain View, CA (United States). NASA Nexus for Exoplanet System Science
NASA Ames Research Center (ARC), Moffett Field, Mountain View, CA (United States)
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Univ. of Arizona, Tucson, AZ (United States). Steward Observatory
Univ. of Texas, Austin, TX (United States)
McGill Univ., Montreal, QC (Canada)
Univ. of Central Florida, Orlando, FL (United States)
W. M. Keck Observatory, Waimea, HI (United States)
Rotational modulations of emission spectra in brown dwarf and exoplanet atmospheres show that clouds are often distributed non-uniformly in these ultracool atmospheres. The spatial heterogeneity in cloud distribution demonstrates the impact of atmospheric dynamics on cloud formation and evolution. In this study, we update the Hubble Space Telescope (HST) time-series data analysis of the previously reported rotational modulations of WISEP J004701+680352—an unusually red late-L brown dwarf with a spectrum similar to that of the directly imaged planet HR 8799e. We construct a self-consistent spatially heterogeneous cloud model to explain the HST and the Spitzer time-series observations, as well as the time-averaged spectra of WISE 0047. Additionally, in the heterogeneous cloud model, a cloud thickness variation of around one pressure scale height explains the wavelength dependence in the HST near-IR spectral variability. By including disequilibrium CO/CH4 chemistry, our models also reproduce the redder $$J-{K}_{{\rm{s}}}$$ color of WISE 0047 compared to that of field brown dwarfs. We discuss the impact of vertical cloud structure on atmospheric profile and estimate the minimum eddy diffusivity coefficient for other objects with redder colors. Our data analysis and forward modeling results demonstrate that time-series spectrophotometry with a broad wavelength coverage is a powerful tool for constraining heterogeneous atmospheric structure.
Lew, Ben P., et al. "Cloud Atlas: Unraveling the Vertical Cloud Structure with the Time-series Spectrophotometry of an Unusually Red Brown Dwarf." The Astrophysical Journal (Online), vol. 903, no. 1, Oct. 2020. https://doi.org/10.3847/1538-4357/abb81d
Lew, Ben P., Apai, Dániel, Marley, Mark, Saumon, Didier, Schneider, Glenn, Zhou, Yifan, Cowan, Nicolas B., Karalidi, Theodora, Manjavacas, Elena, Bedin, L. R., & Miles-Páez, Paulo A. (2020). Cloud Atlas: Unraveling the Vertical Cloud Structure with the Time-series Spectrophotometry of an Unusually Red Brown Dwarf. The Astrophysical Journal (Online), 903(1). https://doi.org/10.3847/1538-4357/abb81d
Lew, Ben P., Apai, Dániel, Marley, Mark, et al., "Cloud Atlas: Unraveling the Vertical Cloud Structure with the Time-series Spectrophotometry of an Unusually Red Brown Dwarf," The Astrophysical Journal (Online) 903, no. 1 (2020), https://doi.org/10.3847/1538-4357/abb81d
@article{osti_1760580,
author = {Lew, Ben P. and Apai, Dániel and Marley, Mark and Saumon, Didier and Schneider, Glenn and Zhou, Yifan and Cowan, Nicolas B. and Karalidi, Theodora and Manjavacas, Elena and Bedin, L. R. and others},
title = {Cloud Atlas: Unraveling the Vertical Cloud Structure with the Time-series Spectrophotometry of an Unusually Red Brown Dwarf},
annote = {Rotational modulations of emission spectra in brown dwarf and exoplanet atmospheres show that clouds are often distributed non-uniformly in these ultracool atmospheres. The spatial heterogeneity in cloud distribution demonstrates the impact of atmospheric dynamics on cloud formation and evolution. In this study, we update the Hubble Space Telescope (HST) time-series data analysis of the previously reported rotational modulations of WISEP J004701+680352—an unusually red late-L brown dwarf with a spectrum similar to that of the directly imaged planet HR 8799e. We construct a self-consistent spatially heterogeneous cloud model to explain the HST and the Spitzer time-series observations, as well as the time-averaged spectra of WISE 0047. Additionally, in the heterogeneous cloud model, a cloud thickness variation of around one pressure scale height explains the wavelength dependence in the HST near-IR spectral variability. By including disequilibrium CO/CH4 chemistry, our models also reproduce the redder $J-{K}_{{\rm{s}}}$ color of WISE 0047 compared to that of field brown dwarfs. We discuss the impact of vertical cloud structure on atmospheric profile and estimate the minimum eddy diffusivity coefficient for other objects with redder colors. Our data analysis and forward modeling results demonstrate that time-series spectrophotometry with a broad wavelength coverage is a powerful tool for constraining heterogeneous atmospheric structure.},
doi = {10.3847/1538-4357/abb81d},
url = {https://www.osti.gov/biblio/1760580},
journal = {The Astrophysical Journal (Online)},
issn = {ISSN 1538-4357},
number = {1},
volume = {903},
place = {United States},
publisher = {Institute of Physics (IOP)},
year = {2020},
month = {10}}
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol. 370, Issue 1968https://doi.org/10.1098/rsta.2011.0269