Optical transmission photometry of the highly inflated exoplanet WASP-17b
Abstract
We present ground-based high-precision observations of the transit of WASP-17b using the multiband photometer ULTRACAM on ESO's New Technology Telescope (NTT) in the context of performing transmission spectrophotometry of this highly inflated exoplanet. Our choice of filters (SDSS u', g' and r' bands) is designed to probe for the presence of opacity sources in the upper atmosphere. We find evidence for a wavelength dependence in the planet radius in the form of enhanced absorption in the SDSS r' band, consistent with a previously detected broad sodium feature. We present a new independent measurement of the planetary radius at Rpl = 1.97 ± 0.06RJ, which confirms this planet as the most inflated exoplanet known to date. Our measurements are most consistent with an atmospheric profile devoid of enhanced TiO opacity, previously predicted to be present for this planet.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- January 2014
- DOI:
- 10.1093/mnras/stt1979
- arXiv:
- arXiv:1310.3893
- Bibcode:
- 2014MNRAS.437.1511B
- Keywords:
-
- stars: individual: WASP-17;
- stars: planetary systems;
- Astrophysics - Earth and Planetary Astrophysics;
- Astrophysics - Instrumentation and Methods for Astrophysics
- E-Print:
- 10 pages, 3 figures, 3 tables. Accepted for MNRAS publication. Corrected typo on error bar for u band measurement