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The First Detection of Photometric Variability in a Y Dwarf: WISE J140518.39+553421.3

Cushing, Michael C. and Hardegree-Ullman, Kevin K. and Trucks, Jesica L. and Morley, Caroline V. and Gizis, John E. and Marley, Mark S. and Fortney, Jonathan J. and Kirkpatrick, J. Davy and Gelino, Christopher R. and Mace, Gregory N. and Carey, Sean J. (2016) The First Detection of Photometric Variability in a Y Dwarf: WISE J140518.39+553421.3. Astrophysical Journal, 823 (2). Art. No. 152. ISSN 0004-637X. doi:10.3847/0004-637X/823/2/152.

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We present the first detection of the photometric variability in a spectroscopically confirmed Y dwarf. The Infrared Array Camera on board the Spitzer Space Telescope was used to obtain time series photometry of WISE J140518.39+553421.3 at 3.6 and 4.5 μm over a 24-hr period at two different epochs separated by 149 days. Variability is evident at 4.5 μm in the first epoch and at 3.6 and 4.5 μm in the second epoch, which suggests that the underlying cause or causes of this variability change on the timescales of months. The second-epoch [3.6] and [4.5] light curves are nearly sinusoidal in form, in phase, have periods of roughly 8.5 hr, and have semi-amplitudes of 3.5%. We find that a simple geometric spot model with a single bright spot reproduces these observations well. We also compare our measured semi-amplitudes of the second-epoch light curves to predictions of the static, one-dimensional, partly cloudy, and hot spot models of Morley and collaborators, and find that neither set of models can reproduce the observed [3.6] and [4.5] semi-amplitudes simultaneously. Therefore, more advanced two-dimensional or three-dimensional models that include time-dependent phenomena like vertical mixing, cloud formation, and thermal relaxation are sorely needed in order to properly interpret our observations.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Cushing, Michael C.0000-0001-7780-3352
Hardegree-Ullman, Kevin K.0000-0003-3702-0382
Morley, Caroline V.0000-0002-4404-0456
Gizis, John E.0000-0002-8916-1972
Marley, Mark S.0000-0002-5251-2943
Fortney, Jonathan J.0000-0002-9843-4354
Kirkpatrick, J. Davy0000-0003-4269-260X
Mace, Gregory N.0000-0001-7875-6391
Carey, Sean J.0000-0002-0221-6871
Additional Information:© 2016 The American Astronomical Society. Received 2015 July 24; accepted 2016 February 17; published 2016 June 1. We thank the anonymous referee for comments that improved the paper. This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administrations and is based [in part] on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech. and the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. This research has made use of the NASA/IPAC Infrared Science Archive, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
NASANAS 5-26555
Subject Keywords:brown dwarfs – infrared: stars – stars: individual (WISE J140518.39+553421.3) – stars: low-mass
Issue or Number:2
Record Number:CaltechAUTHORS:20160701-114019116
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:68812
Deposited By: Tony Diaz
Deposited On:05 Jul 2016 03:17
Last Modified:11 Nov 2021 04:05

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