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Title: A ground-based optical transmission spectrum of WASP-6b

We present a ground-based optical transmission spectrum of the inflated sub-Jupiter-mass planet WASP-6b. The spectrum was measured in 20 spectral channels from 480 nm to 860 nm using a series of 91 spectra over a complete transit event. The observations were carried out using multi-object differential spectrophotometry with the Inamori-Magellan Areal Camera and Spectrograph on the Baade Telescope at Las Campanas Observatory. We model systematic effects on the observed light curves using principal component analysis on the comparison stars and allow for the presence of short and long memory correlation structure in our Monte Carlo Markov Chain analysis of the transit light curves for WASP-6. The measured transmission spectrum presents a general trend of decreasing apparent planetary size with wavelength and lacks evidence for broad spectral features of Na and K predicted by clear atmosphere models. The spectrum is consistent with that expected for scattering that is more efficient in the blue, as could be caused by hazes or condensates in the atmosphere of WASP-6b. WASP-6b therefore appears to be yet another massive exoplanet with evidence for a mostly featureless transmission spectrum, underscoring the importance that hazes and condensates can have in determining the transmission spectra of exoplanets.
Authors:
; ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ; ;  [7] ;  [8] ;  [9]
  1. Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 7820436 Macul, Santiago (Chile)
  2. Departmento de Estadística, Facultad de Matemáticas, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 7820436 Macul, Santiago (Chile)
  3. School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom)
  4. CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States)
  5. Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)
  6. Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)
  7. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  8. Astrophysics Group, Keele University, Staffordshire ST5 5BG (United Kingdom)
  9. Department of Physics, and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)
Publication Date:
OSTI Identifier:
22341913
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 778; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COMPARATIVE EVALUATIONS; CONDENSATES; CORRELATIONS; JUPITER PLANET; LANTHANUM SULFIDES; MARKOV PROCESS; MASS; MONTE CARLO METHOD; SATELLITE ATMOSPHERES; SCATTERING; SPECTRA; SPECTROPHOTOMETRY; STARS; TELESCOPES; TRANSMISSION; VISIBLE RADIATION; WASPS; WAVELENGTHS