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Title: SPECTROSCOPIC EVIDENCE FOR A TEMPERATURE INVERSION IN THE DAYSIDE ATMOSPHERE OF HOT JUPITER WASP-33b

Abstract

We present observations of two occultations of the extrasolar planet WASP-33b using the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope, which allow us to constrain the temperature structure and composition of its dayside atmosphere. WASP-33b is the most highly irradiated hot Jupiter discovered to date, and the only exoplanet known to orbit a δ-Scuti star. We observed in spatial scan mode to decrease instrument systematic effects in the data, and removed fluctuations in the data due to stellar pulsations. The rms for our final, binned spectrum is 1.05 times the photon noise. We compare our final spectrum, along with previously published photometric data, to atmospheric models of WASP-33b spanning a wide range in temperature profiles and chemical compositions. We find that the data require models with an oxygen-rich chemical composition and a temperature profile that increases at high altitude. We find that our measured spectrum displays an excess in the measured flux toward short wavelengths that is best explained as emission from TiO. If confirmed by additional measurements at shorter wavelengths, this planet would become the first hot Jupiter with a thermal inversion that can be definitively attributed to the presence of TiO in its dayside atmosphere.

Authors:
;  [1];  [2];  [3];  [4]
  1. Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
  2. Institute of Astronomy, University of Cambridge, Cambridge CB3 0HA (United Kingdom)
  3. Department of Astronomy, University of Maryland, College Park, MD 20742 (United States)
  4. Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States)
Publication Date:
OSTI Identifier:
22522297
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 806; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CAMERAS; CHEMICAL COMPOSITION; COMPARATIVE EVALUATIONS; ECLIPSE; EMISSION SPECTRA; FLUCTUATIONS; IRRADIATION; JUPITER PLANET; NOISE; ORBITS; OXYGEN; PLANETARY ATMOSPHERES; PULSATIONS; SPACE; STARS; TELESCOPES; TEMPERATURE INVERSIONS; TITANIUM OXIDES; WAVELENGTHS

Citation Formats

Haynes, Korey, Mandell, Avi M., Madhusudhan, Nikku, Deming, Drake, and Knutson, Heather. SPECTROSCOPIC EVIDENCE FOR A TEMPERATURE INVERSION IN THE DAYSIDE ATMOSPHERE OF HOT JUPITER WASP-33b. United States: N. p., 2015. Web. doi:10.1088/0004-637X/806/2/146.
Haynes, Korey, Mandell, Avi M., Madhusudhan, Nikku, Deming, Drake, & Knutson, Heather. SPECTROSCOPIC EVIDENCE FOR A TEMPERATURE INVERSION IN THE DAYSIDE ATMOSPHERE OF HOT JUPITER WASP-33b. United States. https://doi.org/10.1088/0004-637X/806/2/146
Haynes, Korey, Mandell, Avi M., Madhusudhan, Nikku, Deming, Drake, and Knutson, Heather. 2015. "SPECTROSCOPIC EVIDENCE FOR A TEMPERATURE INVERSION IN THE DAYSIDE ATMOSPHERE OF HOT JUPITER WASP-33b". United States. https://doi.org/10.1088/0004-637X/806/2/146.
@article{osti_22522297,
title = {SPECTROSCOPIC EVIDENCE FOR A TEMPERATURE INVERSION IN THE DAYSIDE ATMOSPHERE OF HOT JUPITER WASP-33b},
author = {Haynes, Korey and Mandell, Avi M. and Madhusudhan, Nikku and Deming, Drake and Knutson, Heather},
abstractNote = {We present observations of two occultations of the extrasolar planet WASP-33b using the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope, which allow us to constrain the temperature structure and composition of its dayside atmosphere. WASP-33b is the most highly irradiated hot Jupiter discovered to date, and the only exoplanet known to orbit a δ-Scuti star. We observed in spatial scan mode to decrease instrument systematic effects in the data, and removed fluctuations in the data due to stellar pulsations. The rms for our final, binned spectrum is 1.05 times the photon noise. We compare our final spectrum, along with previously published photometric data, to atmospheric models of WASP-33b spanning a wide range in temperature profiles and chemical compositions. We find that the data require models with an oxygen-rich chemical composition and a temperature profile that increases at high altitude. We find that our measured spectrum displays an excess in the measured flux toward short wavelengths that is best explained as emission from TiO. If confirmed by additional measurements at shorter wavelengths, this planet would become the first hot Jupiter with a thermal inversion that can be definitively attributed to the presence of TiO in its dayside atmosphere.},
doi = {10.1088/0004-637X/806/2/146},
url = {https://www.osti.gov/biblio/22522297}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 806,
place = {United States},
year = {Sat Jun 20 00:00:00 EDT 2015},
month = {Sat Jun 20 00:00:00 EDT 2015}
}