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Extrasolar storms: Pressure-dependent changes in light-curve phase in brown dwarfs from simultaneous HST and SPITZER observations

Yang, Hao and Apai, Dániel and Marley, Mark S. and Karalidi, Theodora and Flateau, Davin and Showman, Adam P. and Metchev, Stanimir and Buenzli, Esther and Radigan, Jacqueline and Artigau, Étienne and Lowrance, Patrick J. and Burgasser, Adam J. (2016) Extrasolar storms: Pressure-dependent changes in light-curve phase in brown dwarfs from simultaneous HST and SPITZER observations. Astrophysical Journal, 826 (1). Art. No. 8. ISSN 0004-637X.

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We present Spitzer/Infrared Array Camera Ch1 and Ch2 monitoring of six brown dwarfs during eight different epochs over the course of 20 months. For four brown dwarfs, we also obtained simulataneous Hubble Space Telescope (HST)/WFC3 G141 grism spectra during two epochs and derived light curves in five narrowband filters. Probing different pressure levels in the atmospheres, the multiwavelength light curves of our six targets all exhibit variations, and the shape of the light curves evolves over the timescale of a rotation period, ranging from 1.4 to 13 hr. We compare the shapes of the light curves and estimate the phase shifts between the light curves observed at different wavelengths by comparing the phase of the primary Fourier components. We use state-of-the-art atmosphere models to determine the flux contribution of different pressure layers to the observed flux in each filter. We find that the light curves that probe higher pressures are similar and in phase, but are offset and often different from the light curves that probe lower pressures. The phase differences between the two groups of light curves suggest that the modulations seen at lower and higher pressures may be introduced by different cloud layers.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Yang, Hao0000-0002-8241-6231
Apai, Dániel0000-0003-3714-5855
Marley, Mark S.0000-0002-5251-2943
Karalidi, Theodora0000-0001-7356-6652
Metchev, Stanimir0000-0003-3050-8203
Radigan, Jacqueline0000-0002-6732-3651
Lowrance, Patrick J.0000-0001-8014-0270
Burgasser, Adam J.0000-0002-6523-9536
Alternate Title:Extrasolar Storms: Pressure-dependent Changes In Light Curve Phase In Brown Dwarfs From Simultaneous Hubble and Spitzer Observations
Additional Information:© 2016 The American Astronomical Society. Received 2016 February 26; revised 2016 May 6; accepted 2016 May 6; published 2016 July 14. This work is part of the Spitzer Cycle-9 Exploration Program, Extrasolar Storms. This work 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. Support for HST GO programs 13176 was provided by Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. We acknowledge the outstanding help of Patricia Royle (STScI) and the Spitzer Science Center staff, especially Nancy Silbermann, for coordinating the HST and Spitzer observations. This research has benefitted from the SpeX Prism Spectral Libraries, maintained by Adam Burgasser at, and the M, L, T, and Y dwarf compendium housed at
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Subject Keywords:brown dwarfs; infrared: stars; stars: atmospheres; stars: low-mass
Issue or Number:1
Record Number:CaltechAUTHORS:20160919-075341094
Persistent URL:
Official Citation:Hao Yang et al 2016 ApJ 826 8
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:70415
Deposited By: Ruth Sustaita
Deposited On:19 Sep 2016 16:24
Last Modified:09 Mar 2020 13:19

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