CLOUD ATLAS: DISCOVERY OF PATCHY CLOUDS AND HIGH-AMPLITUDE ROTATIONAL MODULATIONS IN A YOUNG, EXTREMELY RED L-TYPE BROWN DWARF
AuthorLew, Ben W. P.
Burgasser, Adam J.
Marley, Mark S.
Cowan, Nicolas B.
Bedin, Luigi R.
Metchev, Stanimir A.
Lowrance, Patrick J.
AffiliationUniv Arizona, Dept Planetary Sci, Lunar & Planetary Lab
Univ Arizona, Dept Astron, Steward Observ
MetadataShow full item record
PublisherIOP PUBLISHING LTD
CitationCLOUD ATLAS: DISCOVERY OF PATCHY CLOUDS AND HIGH-AMPLITUDE ROTATIONAL MODULATIONS IN A YOUNG, EXTREMELY RED L-TYPE BROWN DWARF 2016, 829 (2):L32 The Astrophysical Journal
JournalThe Astrophysical Journal
Rights© 2016. The American Astronomical Society. All rights reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at email@example.com.
AbstractCondensate clouds fundamentally impact the atmospheric structure and spectra of exoplanets and brown dwarfs, but the connections between surface gravity, cloud structure, dust in the upper atmosphere, and the red colors of some brown dwarfs remain poorly understood. Rotational modulations enable the study of different clouds in the same atmosphere, thereby providing a method to isolate the effects of clouds. Here, we present the discovery of high peak-to-peak amplitude (8%) rotational modulations in a low-gravity, extremely red (J-K-s = 2.55) L6 dwarf WISEP J004701.06+680352.1 (W0047). Using the Hubble Space Telescope (HST) time-resolved grism spectroscopy, we find a best-fit rotational period (13.20 +/- 0.14 hr) with a larger amplitude at 1.1 mu m than at 1.7 mu m. This is the third-largest near-infrared variability amplitude measured in a brown dwarf, demonstrating that large-amplitude variations are not limited to the L/T transition but are present in some extremely red L-type dwarfs. We report a tentative trend between the wavelength dependence of relative amplitude, possibly proxy for small dust grains lofted in the upper atmosphere, and the likelihood of large-amplitude variability. By assuming forsterite as a haze particle, we successfully explain the wavelength-dependent amplitude with submicron-sized haze particle sizes of around 0.4 mu m. W0047 links the earlier spectral and later spectral type brown dwarfs in which rotational modulations have been observed; the large amplitude variations in this object make this a benchmark brown dwarf for the study of cloud properties close to the L/T transition.
VersionFinal published version
SponsorsTechnology Research Initiative Fund (TRIF) Imaging Fellowship, University of Arizona; NASA through a grant from the Space Telescope Science Institute ; NASA [NAS5-26555]; Space Telescope Science Institute ; National Aeronautics and Space Administration; National Science Foundation