TRANSMISSION SPECTROSCOPY OF THE HOT JUPITER WASP-12b FROM 0.7 TO 5 μm

By Kevin B. Stevenson, J. Bean, A. Seifahrt, J. D'esert, N. Madhusudhan, M. Bergmann, Laura Kreidberg, Derek Homeier. 2013

149 citations recorded by the source corpus.

Since the first report of a potentially non-solar carbon-to-oxygen ratio (C/O) in its dayside atmosphere, the highly irradiated exoplanet WASP-12b has been under intense scrutiny and the subject of many follow-up observations. Additionally, the recent discovery of stellar binary companions ∼1″ from WASP-12 has obfuscated interpretation of the observational data. Here we present new ground-based multi-object transmission-spectroscopy observations of WASP-12b that we acquired over two consecutive nights in the red optical with Gemini-N/GMOS. After correcting for the influence of WASP-12's stellar companions, we find that these data rule out a cloud-free H2 atmosphere with no additional opacity sources. We detect features in the transmission spectrum that may be attributed to metal oxides (such as TiO and VO) for an O-rich atmosphere or to metal hydrides (such as TiH) for a C-rich atmosphere. We also reanalyzed NIR transit-spectroscopy observations of WASP-12b from HST/WFC3 and broadband transit photometry from Warm Spitzer. We attribute the broad spectral features in the WFC3 data to either H2O or CH4 and HCN for an O-rich or C-rich atmosphere, respectively. The Spitzer data suggest shallower transit depths than the models predict at infrared wavelengths, albeit at low statistical significance. A multi-instrument, broad-wavelength analysis of WASP-12b suggests that the transmission spectrum is well approximated by a simple Rayleigh scattering model with a planet terminator temperature of 1870 ± 130 K. We conclude that additional high-precision data and isolated spectroscopic measurements of the companion stars are required to place definitive constraints on the composition of WASP-12b's atmosphere.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/10dee9f9fd89691f89b6cc6b5bd596040e29db78

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In Astronomy and Astrophysics

  1. N. Madhusudhan
  2. Jon Fortney
  3. M. Line
  4. A. Showman
  5. Laura Kreidberg
  6. J. D'esert
  7. J. Bean
  8. Kevin B. Stevenson

In Instrumentation

  1. N. Madhusudhan
  2. M. Line
  3. Jon Fortney
  4. Laura Kreidberg
  5. A. Showman
  6. J. D'esert
  7. J. Bean
  8. Kevin B. Stevenson

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