TY - JOUR
T1 - Cloud Atlas
T2 - Discovery of Rotational Spectral Modulations in a Low-mass, L-type Brown Dwarf Companion to a Star
AU - Manjavacas, Elena
AU - Apai, Dániel
AU - Zhou, Yifan
AU - Karalidi, Theodora
AU - Lew, Ben W.P.
AU - Schneider, Glenn
AU - Cowan, Nicolas
AU - Metchev, Stan
AU - Miles-Páez, Paulo A.
AU - Burgasser, Adam J.
AU - Radigan, Jacqueline
AU - Bedin, Luigi R.
AU - Lowrance, Patrick J.
AU - Marley, Mark S.
N1 - Funding Information:
We thank our referee Dr. Derek Homeier for his valuable comments that improved this work. This study is based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555, under GO-14241. This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation.
Publisher Copyright:
© 2017 The American Astronomical Society. All rights reserved.
PY - 2018/1
Y1 - 2018/1
N2 - Observations of rotational modulations of brown dwarfs and giant exoplanets allow the characterization of condensate cloud properties. As of now, rotational spectral modulations have only been seen in three L-type brown dwarfs. We report here the discovery of rotational spectral modulations in LP261-75B, an L6-type intermediate surface gravity companion to an M4.5 star. As a part of the Cloud Atlas Treasury program, we acquired time-resolved Wide Field Camera 3 grism spectroscopy (1.1-1.69 μm) of LP261-75B. We find gray spectral variations with the relative amplitude displaying only a weak wavelength dependence and no evidence for lower-amplitude modulations in the 1.4 μm water band than in the adjacent continuum. The likely rotational modulation period is 4.78 ± 0.95 hr, although the rotational phase is not well sampled. The minimum relative amplitude in the white light curve measured over the whole wavelength range is 2.41% ± 0.14%. We report an unusual light curve, which seems to have three peaks approximately evenly distributed in rotational phase. The spectral modulations suggests that the upper atmosphere cloud properties in LP261-75B are similar to two other mid-L dwarfs of typical infrared colors, but differ from that of the extremely red L-dwarf WISE0047.
AB - Observations of rotational modulations of brown dwarfs and giant exoplanets allow the characterization of condensate cloud properties. As of now, rotational spectral modulations have only been seen in three L-type brown dwarfs. We report here the discovery of rotational spectral modulations in LP261-75B, an L6-type intermediate surface gravity companion to an M4.5 star. As a part of the Cloud Atlas Treasury program, we acquired time-resolved Wide Field Camera 3 grism spectroscopy (1.1-1.69 μm) of LP261-75B. We find gray spectral variations with the relative amplitude displaying only a weak wavelength dependence and no evidence for lower-amplitude modulations in the 1.4 μm water band than in the adjacent continuum. The likely rotational modulation period is 4.78 ± 0.95 hr, although the rotational phase is not well sampled. The minimum relative amplitude in the white light curve measured over the whole wavelength range is 2.41% ± 0.14%. We report an unusual light curve, which seems to have three peaks approximately evenly distributed in rotational phase. The spectral modulations suggests that the upper atmosphere cloud properties in LP261-75B are similar to two other mid-L dwarfs of typical infrared colors, but differ from that of the extremely red L-dwarf WISE0047.
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U2 - 10.3847/1538-3881/aa984f
DO - 10.3847/1538-3881/aa984f
M3 - Article
AN - SCOPUS:85040441492
SN - 0004-6256
VL - 155
JO - Astronomical Journal
JF - Astronomical Journal
IS - 1
M1 - 11
ER -