Optical transmission photometry of the highly inflated exoplanet WASP-17b★

Bento, J.; Wheatley, P. J.; Copperwheat, C. M.; Fortney, J. J.; Dhillon, V. S.; Hickman, R.; Littlefair, S. P.; Marsh, T. R.; Parsons, S. G.; Southworth, J.

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.

Citation

Bento, J., Wheatley, P. J., Copperwheat, C. M., Fortney, J. J., Dhillon, V. S., Hickman, R., …Southworth, J. (2014). Optical transmission photometry of the highly inflated exoplanet WASP-17b★. Monthly Notices of the Royal Astronomical Society, 437(2), 1511-1518. https://doi.org/10.1093/mnras/stt1979

• Journal Article Type: Article
• Acceptance Date: Oct 14, 2013
• Online Publication Date: Nov 15, 2013
• Publication Date: Jan 11, 2014
• Deposit Date: Jun 16, 2023
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 0035-8711
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 437
• Issue: 2
• Pages: 1511-1518
• DOI: https://doi.org/10.1093/mnras/stt1979
• Keywords: Space and Planetary Science; Astronomy and Astrophysics; stars: individual: WASP-17; stars: planetary systems
• Publisher URL: https://academic.oup.com/mnras/article/437/2/1511/1103641