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Exoplanet Transit Spectroscopy Using WFC3: WASP-12 b, WASP-17 b, and WASP-19 bWe report an analysis of transit spectroscopy of the extrasolar planets WASP-12 b, WASP-17 b, and WASP-19 b using the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST). We analyze the data for a single transit for each planet using a strategy similar, in certain aspects, to the techniques used by Berta et al., but we extend their methodology to allow us to correct for channel- or wavelength-dependent instrumental effects by utilizing the band-integrated time series and measurements of the drift of the spectrum on the detector over time. We achieve almost photon-limited results for individual spectral bins, but the uncertainties in the transit depth for the band-integrated data are exacerbated by the uneven sampling of the light curve imposed by the orbital phasing of HST's observations. Our final transit spectra for all three objects are consistent with the presence of a broad absorption feature at 1.4 nano meter most likely due to water. However, the amplitude of the absorption is less than that expected based on previous observations with Spitzer, possibly due to hazes absorbing in the NIR or non-solar compositions. The degeneracy of models with different compositions and temperature structures combined with the low amplitude of any features in the data preclude our ability to place unambiguous constraints on the atmospheric composition without additional observations with WFC3 to improve the signal-to-noise ratio and/or a comprehensive multi-wavelength analysis.
Document ID
20140010289
Document Type
Reprint (Version printed in journal)
Authors
Mandell, Avram Max (NASA Goddard Space Flight Center Greenbelt, MD United States)
Haynes, Korey N. (George Mason Univ. Fairfax, VA, United States)
Sinukoff, Evan (Hawaii Univ. Honolulu, HI, United States)
Madhusudhan, Nikku (Yale Univ. New Haven, CT, United States)
Burrows, Adam (Princeton Univ. Princeton, NJ, United States)
Deming, Drake (Maryland Univ. College Park, MD, United States)
Date Acquired
July 29, 2014
Publication Date
December 20, 2013
Publication Information
Publication: The Astrophysical Journal
Volume: 779
Issue: 2
Subject Category
Astronomy
Astrophysics
Report/Patent Number
GSFC-E-DAA-TN10468
Funding Number(s)
CONTRACT_GRANT: HST-GO-12314.03-A
CONTRACT_GRANT: JPL/Spitzer Agreement 1371432
CONTRACT_GRANT: JPL/Spitzer Agreement 1377197
CONTRACT_GRANT: HST-GO-12181.04-A
CONTRACT_GRANT: NNX07AG80G
CONTRACT_GRANT: JPL/Spitzer Agreement 1417122
CONTRACT_GRANT: JPL/Spitzer Agreement 1348668
Distribution Limits
Public
Copyright
Other
Keywords
Atmospheres
Exoplanets
HST