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Cloud Atlas: Discovery of Rotational Spectral Modulations in a Low-mass, L-type Brown Dwarf Companion to a Star

Manjavacas, Elena and Apai, Dániel and Zhou, Yifan and Karalidi, Theodora and Lew, Ben W. P. and Schneider, Glenn and Cowan, Nicolas and Metchev, Stan and Miles-Páez, Paulo A. and Burgasser, Adam J. and Radigan, Jacqueline and Bedin, Luigi R. and Lowrance, Patrick J. and Marley, Mark S. (2018) Cloud Atlas: Discovery of Rotational Spectral Modulations in a Low-mass, L-type Brown Dwarf Companion to a Star. Astronomical Journal, 155 (1). Art. No. 11. ISSN 1538-3881. doi:10.3847/1538-3881/aa984f.

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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.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Manjavacas, Elena0000-0003-0192-6887
Apai, Dániel0000-0003-3714-5855
Zhou, Yifan0000-0003-2969-6040
Karalidi, Theodora0000-0001-7356-6652
Lew, Ben W. P.0000-0003-1487-6452
Schneider, Glenn0000-0002-4511-5966
Cowan, Nicolas0000-0001-6129-5699
Metchev, Stan0000-0003-3050-8203
Miles-Páez, Paulo A.0000-0003-2446-8882
Burgasser, Adam J.0000-0002-6523-9536
Radigan, Jacqueline0000-0002-6732-3651
Bedin, Luigi R.0000-0003-4080-6466
Lowrance, Patrick J.0000-0001-8014-0270
Marley, Mark S.0000-0002-5251-2943
Additional Information:© 2017 The American Astronomical Society. Received 2017 August 10; revised 2017 October 20; accepted 2017 October 22; published 2017 December 12. 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. Software: IDL®, (Markwardt 2009).
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
NASANAS 5-26555
Subject Keywords:brown dwarfs – stars: atmospheres
Issue or Number:1
Record Number:CaltechAUTHORS:20171212-123348142
Persistent URL:
Official Citation:Elena Manjavacas et al 2018 AJ 155 11
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:83828
Deposited By: Tony Diaz
Deposited On:12 Dec 2017 21:36
Last Modified:15 Nov 2021 20:14

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