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The Broadband Infrared Emission Spectrum of the Exoplanet HD 189733b

Charbonneau, David and Knutson, Heather A. and Barman, Travis and Allen, Lori E. and Mayor, Michel and Megeath, S. Thomas and Queloz, Didier and Udry, Stéphane (2008) The Broadband Infrared Emission Spectrum of the Exoplanet HD 189733b. Astrophysical Journal, 686 (2). pp. 1341-1348. ISSN 0004-637X. doi:10.1086/591635.

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We present Spitzer Space Telescope time series photometry of the exoplanet system HD 189733 spanning two times of secondary eclipse, when the planet passes out of view behind the parent star. We estimate the relative eclipse depth in five distinct bands and find the planet-to-star flux ratio to be 0.256% ± 0.014% (3.6 μm), 0.214% ± 0.020% (4.5 μm), 0.310% ± 0.034% (5.8 μm), 0.391% ± 0.022% (8.0 μm), and 0.598% ± 0.038% (24 μm). For consistency, we reanalyze a previously published time series to deduce a contrast ratio in an additional band, 0.519% ± 0.020% (16 μm). Our data are strongly inconsistent with a Planck spectrum, and we clearly detect emission near 4 μm as predicted by published theoretical models in which this feature arises from a corresponding opacity window. Unlike recent results for the exoplanet HD 209458b, we find that the emergent spectrum from HD 189733b is best matched by models that do not include an atmospheric temperature inversion. Taken together, these two studies provide initial observational support for the idea that hot Jupiter atmospheres diverge into two classes, in which a thermal inversion layer is present for the more strongly irradiated objects.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Charbonneau, David0000-0002-9003-484X
Knutson, Heather A.0000-0002-0822-3095
Barman, Travis0000-0002-7129-3002
Megeath, S. Thomas0000-0001-7629-3573
Queloz, Didier0000-0002-3012-0316
Additional Information:© 2008 American Astronomical Society. Received 2008 February 6; accepted 2008 July 7. This work is based 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. H. A. K. was supported by a National Science Foundation Graduate Research Fellowship. Facilities: Spitzer ( IRAC, IRS, MIPS).
Group:Infrared Processing and Analysis Center (IPAC), Division of Geological and Planetary Sciences
Funding AgencyGrant Number
NSF Graduate Research FellowshipUNSPECIFIED
Issue or Number:2
Record Number:CaltechAUTHORS:20130129-105835699
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Official Citation:The Broadband Infrared Emission Spectrum of the Exoplanet HD 189733b David Charbonneau et al. 2008 ApJ 686 1341
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:36645
Deposited By: Ruth Sustaita
Deposited On:29 Jan 2013 19:18
Last Modified:09 Nov 2021 23:23

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