Wilkins, Ashlee N. and Deming, Drake and Madhusudhan, Nikku and Burrows, Adam and Knutson, Heather and McCullough, Peter R. and Ranjan, Sukrit (2014) The Emergent 1.1-1.7 μm Spectrum of the Exoplanet CoRoT-2b as Measured Using the Hubble Space Telescope. Astrophysical Journal, 783 (2). Art. No. 113. ISSN 0004-637X. doi:10.1088/0004-637X/783/2/113. https://resolver.caltech.edu/CaltechAUTHORS:20140617-134424051
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Abstract
We have used Hubble/WFC3 and the G141 grism to measure the secondary eclipse of the transiting, very hot Jupiter CoRoT-2b in the 1.1-1.7 μm spectral region. We find an eclipse depth averaged over this band equal to 395^(+69)_(-45) parts per million, equivalent to a blackbody temperature of 1788 ± 18 K. We study and characterize several WFC3 instrumental effects, especially the "hook" phenomenon described by Deming et al. We use data from several transiting exoplanet systems to find a quantitative relation between the amplitude of the hook and the exposure level of a given pixel. Although the uncertainties in this relation are too large to allow us to develop an empirical correction for our data, our study provides a useful guide for optimizing exposure levels in future WFC3 observations. We derive the planet's spectrum using a differential method. The planet-to-star contrast increases to longer wavelength within the WFC3 bandpass, but without water absorption or emission to a 3σ limit of 85 ppm. The slope of the WFC3 spectrum is significantly less than the slope of the best-fit blackbody. We compare all existing eclipse data for this planet to a blackbody spectrum, and to spectra from both solar abundance and carbon-rich (C/O = 1) models. A blackbody spectrum is an acceptable fit to the full data set. Extra continuous opacity due to clouds or haze, and flattened temperature profiles, are strong candidates to produce quasi-blackbody spectra, and to account for the amplitude of the optical eclipses. Our results show ambiguous evidence for a temperature inversion in this planet.
Item Type: | Article | ||||||||||||
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Alternate Title: | The Emergent 1.1-1.7 Micron Spectrum of the Exoplanet CoRoT-2b as Measured Using the Hubble Space Telescope | ||||||||||||
Additional Information: | © 2014 American Astronomical Society. Received 2013 October 18; accepted 2014 January 16; published 2014 February 21. | ||||||||||||
Subject Keywords: | planets and satellites: atmospheres; planets and satellites: individual (CoRoT-2b); stars: individual (CoRoT-2); techniques: photometric; techniques: spectroscopic | ||||||||||||
Issue or Number: | 2 | ||||||||||||
DOI: | 10.1088/0004-637X/783/2/113 | ||||||||||||
Record Number: | CaltechAUTHORS:20140617-134424051 | ||||||||||||
Persistent URL: | https://resolver.caltech.edu/CaltechAUTHORS:20140617-134424051 | ||||||||||||
Official Citation: | The Emergent 1.1-1.7 μm Spectrum of the Exoplanet CoRoT-2b as Measured Using the Hubble Space Telescope Ashlee N. Wilkins et al. 2014 ApJ 783 113 | ||||||||||||
Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. | ||||||||||||
ID Code: | 46311 | ||||||||||||
Collection: | CaltechAUTHORS | ||||||||||||
Deposited By: | Ruth Sustaita | ||||||||||||
Deposited On: | 17 Jun 2014 21:09 | ||||||||||||
Last Modified: | 10 Nov 2021 17:23 |
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