Discovery of WASP-65b and WASP-75b: Two hot Jupiters without highly inflated radii^⋆

¹ Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
e-mail: y.gomez@warwick.ac.uk
² Physics and Astronomy Department, Vanderbilt University, Nashville, Tennessee 37235, USA
³ Centro de Radioastronomía y Astrofísica, UNAM, Apartado Postal 3-72, 58089 Morelia, Michoacán, México
⁴ School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, UK
⁵ Astrophysics Group, Keele University, Staffordshire, ST5 5BG, UK
⁶ Observatoire astronomique de l’Université de Genève, 51 ch. des Maillettes, 1290 Sauverny, Switzerland
⁷ Université de Liège, Allée du 6 août 17, Sart Tilman, Liège 1, 4000 Liège, Belgium
⁸ Department of Physics, and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
⁹ Aix-Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, 13388 Marseille, France
¹⁰ Department of Physics and Astronomy, Macquarie University, NSW 2109 Sydney, Australia
¹¹ Institut d’Astrophysique de Paris, UMR7095 CNRS, Université Pierre & Marie Curie, 75014 Paris, France
¹² Observatoire de Haute-Provence, CNRS/OAMP, 04870 St Michel l’ Observatoire, France
¹³ Department of Physical Sciences, The Open University, Milton Keynes, MK7 6AA, UK
¹⁴ Max Planck Institut für Extraterrestrische Physik, Giessenbachstrasse 1, 85748 Garching, Germany
¹⁵ Isaac Newton Group of Telescopes, Apartado de Correos 321, 38700 Santa Cruz de Palma, Spain
¹⁶ Department of Physics, University of Cambridge, J J Thomson Av, Cambridge, CB3 0HE, UK
¹⁷ Observatori Astronòmic de Mallorca, Camí de l’Observatori s/n, 07144 Costitx, Mallorca, Spain
¹⁸ Department of Physics, Fisk University, Nashville, Tennessee 37208, USA
¹⁹ Astrophysics Research Centre, Queen’s University Belfast, University Road, Belfast BT7 1NN, UK

Received: 18 July 2013
Accepted: 27 September 2013

Abstract

We report the discovery of two transiting hot Jupiters, WASP-65b (M_pl = 1.55 ± 0.16 M_J; R_pl = 1.11 ± 0.06 R_J), and WASP-75b (M_pl = 1.07 ± 0.05 M_J; R_pl = 1.27 ± 0.05 R_J). They orbit their host star every ~2.311, and ~2.484 days, respectively. The planet host WASP-65 is a G6 star (T_eff = 5600 K, [Fe/H] = −0.07 ± 0.07, age ≳8 Gyr); WASP-75 is an F9 star (T_eff = 6100 K, [Fe/H] = 0.07 ± 0.09, age ~ 3 Gyr). WASP-65b is one of the densest known exoplanets in the mass range 0.1 and 2.0 M_J (ρ_pl = 1.13 ± 0.08 ρ_J), a mass range where a large fraction of planets are found to be inflated with respect to theoretical planet models. WASP-65b is one of only a handful of planets with masses of ~1.5 M_J, a mass regime surprisingly underrepresented among the currently known hot Jupiters. The radius of WASP-75b is slightly inflated (≲10%) as compared to theoretical planet models with no core, and has a density similar to that of Saturn (ρ_pl = 0.52 ± 0.06 ρ_J).