The GTC exoplanet transit spectroscopy survey II: An overly-large Rayleigh-like feature for exoplanet TrES-3b

Abstract

We set to search for Rayleigh scattering and K and Na absorption signatures from the atmosphere of TrES-3b using ground-based transmission spectroscopy covering the wavelength range from 530 to 950 nm as observed with OSIRIS@GTC. Our analysis is based on a Bayesian approach where the light curves covering a set of given passbands are fitted jointly with PHOENIX-calculated stellar limb darkening profiles. The analysis is carried out assuming both white and red -- temporally correlated -- noise, with two approaches (Gaussian processes and divide-by-white) to account for the red noise. An initial analysis reveals a transmission spectrum that shows a strong Rayleigh-like increase in extinction towards the blue end of the spectrum, and enhanced extinction around the K I resonance doublet near 767 nm. However, the signal amplitudes are significantly larger than expected from theoretical considerations. A detailed analysis reveals that the K I-like feature is entirely due to variability in the telluric O${}_2$ absorption, but the Rayleigh-like feature remains unexplained.

12 pages, accepted to A&A

References in corpus (8)

• The NumPy array: a structure for efficient numerical computation
• Improved parameters for extrasolar transiting planets
• PyTransit: Fast and Easy Exoplanet Transit Modelling in Python
• Impact of occultations of stellar active regions on transmission spectra: Can occultation of a plage mimic the signature of a blue sky?
• A transit timing analysis of nine RISE light curves of the exoplanet system TrES-3
• The Transit Light Curve Project. VIII. Six Occultations of the Exoplanet TrES-3
• Near-UV and optical observations of the transiting exoplanet TrES-3b
• Preliminary Results on HAT-P-4, TrES-3, XO-2, and GJ 436 from the NASA EPOXI Mission

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