Physical properties of the WASP-67 planetary system from multi-colour photometry

Abstract

The extrasolar planet WASP-67 b is the first hot Jupiter definitively known to undergo only partial eclipses. The lack of the second and third contact point in this planetary system makes it difficult to obtain accurate measurements of its physical parameters. Aims. By using new high-precision photometric data, we confirm that WASP-67 b shows grazing eclipses and compute accurate estimates of the physical properties of the planet and its parent star. Methods. We present high-quality, multi-colour, broad-band photometric observations comprising five light curves covering two transit events, obtained using two medium-class telescopes and the telescope-defocussing technique. One transit was observed through a Bessel-R filter and the other simultaneously through filters similar to Sloan griz. We modelled these data using jktebop. The physical parameters of the system were obtained from the analysis of these light curves and from published spectroscopic measurements. Results. All five of our light curves satisfy the criterion for being grazing eclipses. We revise the physical parameters of the whole WASP-67 system and, in particular, significantly improve the measurements of the planet's radius and density as compared to the values in the discovery paper. The transit ephemeris was also substantially refined. We investigated the variation of the planet's radius as a function of the wavelength, using the simultaneous multi-band data, finding that our measurements are consistent with a flat spectrum to within the experimental uncertainties.

10 pages, 8 figures, 5 tables, to appear in Astronomy & Astrophysics

References in corpus (10)

• The Dartmouth Stellar Evolution Database
• The K2 Mission: Characterization and Early results
• GROND - a 7-channel imager
• Homogeneous studies of transiting extrasolar planets. I. Light curve analyses
• The Transit Light Curve Project. IX. Evidence for a Smaller Radius of the Exoplanet XO-3b
• Using Stellar Limb-Darkening to Refine the Properties of HD 209458b
• High accuracy transit photometry of the planet OGLE-TR-113b with a new deconvolution-based method
• Updated parameters for the transiting exoplanet WASP-3b using RISE, a new fast camera for the Liverpool Telescope
• A lower radius and mass for the transiting extrasolar planet HAT-P-8b
• Physical properties of the WASP-44 planetary system from simultaneous multi-colour photometry

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• ExoClock project II: A large-scale integrated study with 180 updated exoplanet ephemerides
• The Two-Colour EMCCD Instrument for the Danish 1.54m Telescope and SONG
• A comparative study of WASP-67b and HAT-P-38b from WFC3 data
• Physical properties of the HAT-P-23 and WASP-48 planetary systems from multi-colour photometry
• Exoplanet Interior Retrievals: core masses and metallicities from atmospheric abundances
• Kepler-447b: a hot-Jupiter with an extremely grazing transit
• The TESS Triple-9 Catalog: 999 uniformly vetted candidate exoplanets
• Nauyaca: a new tool to determine planetary masses and orbital elements through transit timing analysis