TY - JOUR
T1 - A ground-based optical transmission spectrum of WASP-6b
AU - Jordán, Andrés
AU - Espinoza, Néstor
AU - Rabus, Markus
AU - Eyheramendy, Susana
AU - Sing, David K.
AU - Désert, Jean Michel
AU - Bakos, Gáspár Á
AU - Fortney, Jonathan J.
AU - López-Morales, Mercedes
AU - Maxted, Pierre F.L.
AU - Triaud, Amaury H.M.J.
AU - Szentgyorgyi, Andrew
PY - 2013/12/1
Y1 - 2013/12/1
N2 - 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.
AB - 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.
KW - planetary systems
KW - planets and satellites: atmospheres
KW - techniques: spectroscopic
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U2 - 10.1088/0004-637X/778/2/184
DO - 10.1088/0004-637X/778/2/184
M3 - Article
AN - SCOPUS:84887876414
SN - 0004-637X
VL - 778
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 184
ER -