The GTC exoplanet transit spectroscopy survey II. An overly large Rayleigh-like feature for exoplanet TrES-3b
2016 | journal article. A publication with affiliation to the University of Göttingen.
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The GTC exoplanet transit spectroscopy survey II. An overly large Rayleigh-like feature for exoplanet TrES-3b
Parviainen, H.; Palle, E.; Nortmann, L.; Nowak, G.; Iro, N.; Murgas, F. & Aigrain, S. (2016)
Astronomy and Astrophysics, 585 art. A114. DOI: https://doi.org/10.1051/0004-6361/201526313
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- Authors
- Parviainen, H.; Palle, E.; Nortmann, L.; Nowak, G.; Iro, N.; Murgas, F.; Aigrain, S.
- Abstract
- Aims. We 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 the OSIRIS instrument at the Gran Telescopio CANARIAS. Methods. 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 noise that is temporally correlated, with two approaches (Gaussian processes and divide-by-white) to account for the red noise. Results. 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.
- Issue Date
- 2016
- Status
- published
- Publisher
- Edp Sciences S A
- Journal
- Astronomy and Astrophysics
- Organization
- Fakultät für Physik
- ISSN
- 1432-0746