Volume 525, January 2011
|Number of page(s)||6|
|Section||Planets and planetary systems|
|Published online||01 December 2010|
WASP-38b: a transiting exoplanet in an eccentric, 6.87d period orbit⋆
Astrophysics Research Centre, School of Mathematics & Physics,
Queen’s University Belfast, University Road,
2 SUPA, School of Physics & Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK
3 Las Cumbres Observatory, 6740 Cortona Drive Suite 102, Goleta, CA 93117, USA
4 Astrophysics Group, Keele University, Staffordshire, ST5 5BG, UK
5 Observatoire de Geneve, Université de Geneve, 51 Ch. des Maillettes, 1290 Sauverny, Switzerland
6 Institut d’Astrophysique de Paris, UMR7095 CNRS, Université Pierre & Marie Curie, 75014 Paris, France
7 Observatoire de Haute-Provence, CNRS/OAMP, 04870 Saint-Michel l’Observatoire, France
8 Laboratoire d’Astrophysique de Marseille, Université d’Aix-Marseille & CNRS, 38 rue Frédéric Joliot-Curie, 13388 Marseille Cedex 13, France
9 Department of Physics, University of Warwick, Coventry CV4 7AL, UK
10 Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UK
11 Department of Physics and Astronomy, The Open University, Milton Keynes MK7 6AA, UK
12 Isaac Newton Group of Telescopes, Apartado de Correos 321, 38700 Santa Cruz de la Palma, Tenerife, Spain
Accepted: 21 October 2010
Aims. We report the discovery of WASP-38b, a long period transiting planet in an eccentric 6.871815 day orbit. The transit epoch is 2 455 335.92050 ± 0.00074 (HJD) and the transit duration is 4.663 h.
Methods. WASP-38b’s discovery was enabled due to an upgrade to the SuperWASP-North cameras. We performed a spectral analysis of the host star HD 146389/BD+10 2980 that yielded Teff = 6150 ± 80 K, log g = 4.3 ± 0.1, vsini = 8.6 ± 0.4 km s-1, M∗ = 1.16 ± 0.04 M⊙ and R∗ = 1.33 ± 0.03 R⊙, consistent with a dwarf of spectral type F8. Assuming a main-sequence mass-radius relation for the star, we fitted simultaneously the radial velocity variations and the transit light curves to estimate the orbital and planetary parameters.
Results. The planet has a mass of 2.69 ± 0.06 MJup and a radius of 1.09 ± 0.03 RJup giving a density, ρp = 2.1 ± 0.1 ρJ. The high precision of the eccentricity e = 0.0314 ± 0.0044 is due to the relative transit timing from the light curves and the RV shape. The planet equilibrium temperature is estimated at 1292 ± 33 K. WASP-38b is the longest period planet found by SuperWASP-North and with a bright host star (V = 9.4 mag), is a good candidate for followup atmospheric studies.
Key words: planets and satellites: detection / stars: individual: WASP-38 / techniques: photometric / techniques: radial velocities
Photometry and RV data are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (22.214.171.124) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/525/A54
© ESO, 2010
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