[en] We present new ground-based, multi-colour, broad-band photometric measurements of the physical parameters, transmission and emission spectra of the transiting extrasolar planet WASP-19b. The measurements are based on observations of eight transits and four occultations through a Gunn i filter using the 1.54-m Danish Telescope, 14 transits through an R[SUB]c[/SUB] filter at the Perth Exoplanet Survey Telescope (PEST) observatory and one transit observed simultaneously through four optical (Sloan g[SUP]'[/SUP], r[SUP]'[/SUP], i[SUP]'[/SUP], z[SUP]'[/SUP]) and three near-infrared (J, H, K) filters, using the Gamma Ray Burst Optical and Near-Infrared Detector (GROND) instrument on the MPG/ESO 2.2-m telescope. The GROND optical light curves have a point-to-point scatter around the best-fitting model between 0.52 and 0.65 mmag rms. We use these new data to measure refined physical parameters for the system. We find the planet to be more bloated (R[SUB]b[/SUB] = 1.410 ± 0.017R[SUB]Jup[/SUB]; M[SUB]b[/SUB] = 1.139 ± 0.030M[SUB]Jup[/SUB]) and the system to be twice as old as initially thought. We also used published and archived data sets to study the transit timings, which do not depart from a linear ephemeris. We detected an anomaly in the GROND transit light curve which is compatible with a spot on the photosphere of the parent star. The starspot position, size, spot contrast and temperature were established. Using our new and published measurements, we assembled the planet's transmission spectrum over the 370-2350 nm wavelength range and its emission spectrum over the 750-8000 nm range. By comparing these data to theoretical models we investigated the theoretically predicted variation of the apparent radius of WASP-19b as a function of wavelength and studied the composition and thermal structure of its atmosphere. We conclude that: (i) there is no evidence for strong optical absorbers at low pressure, supporting the common idea that the planet's atmosphere lacks a dayside inversion; (ii) the temperature of the planet is not homogenized, because the high warming of its dayside causes the planet to be more efficient in re-radiating than redistributing energy to the night side; (iii) the planet seems to be outside of any current classification scheme.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Mancini, L.; Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany ; Department of Physics, University of Salerno, I-84084-Fisciano (SA), Italy
Ciceri, S.; Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany
Chen, G.; Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany ; Purple Mountain Observatory & Key Laboratory for Radio Astronomy, 2 West Beijing Road, Nanjing 210008, China
Tregloan-Reed, J.; Astrophysics Group, Keele University, Staffordshire ST5 5BG, UK
Fortney, J. J.; Department of Astronomy & Astrophysics, University of California, Santa Cruz, CA 95064, USA
Southworth, J.; Astrophysics Group, Keele University, Staffordshire ST5 5BG, UK
Tan, T. G.; Perth Exoplanet Survey Telescope, Perth, Australia
Burgdorf, M.; HE Space Operations GmbH, Flughafenallee 24, D-28199 Bremen, Germany
Calchi Novati, S.; Department of Physics, University of Salerno, I-84084-Fisciano (SA), Italy ; Istituto Internazionale per gli Alti Studi Scientifici (IIASS), I-84019 Vietri Sul Mare (SA), Italy
Dominik, M.; SUPA, University of St Andrews, School of Physics & Astronomy, North Haugh, St Andrews KY16 9SS, UK
Fang, X.-S.; National Astronomical Observatories/Yunnan Observatory, Chinese Academy of Sciences, Kunming 650011, China
Finet, F.; Institut d'Astrophysique et de Géophysique, Université de Liège, B-4000 Liège, Belgium
Gerner, T.; Zentrum für Astronomie, Universität Heidelberg, Mönchhofstraße 12-14, D-69120 Heidelberg, Germany
Hardis, S.; Niels Bohr Institute, University of Copenhagen, Juliane Maries vej 30, DK-2100 Copenhagen Ø, Denmark ; Centre for Star and Planet Formation, Geological Museum, Øster Voldgade 5-7, DK-1350 Copenhagen, Denmark
Hinse, T. C.; Korea Astronomy and Space Science Institute, Daejeon 305-348, Republic of Korea
Jørgensen, U. G.; Niels Bohr Institute, University of Copenhagen, Juliane Maries vej 30, DK-2100 Copenhagen Ø, Denmark ; Centre for Star and Planet Formation, Geological Museum, Øster Voldgade 5-7, DK-1350 Copenhagen, Denmark
Liebig, C.; SUPA, University of St Andrews, School of Physics & Astronomy, North Haugh, St Andrews KY16 9SS, UK
Nikolov, N.; Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany ; Astrophysics Group, University of Exeter, Stocker Road, Exeter EX4 4QL, UK
Ricci, Davide ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS)
Schönebeck, F.; Zentrum für Astronomie, Universität Heidelberg, Mönchhofstraße 12-14, D-69120 Heidelberg, Germany
Skottfelt, J.; Niels Bohr Institute, University of Copenhagen, Juliane Maries vej 30, DK-2100 Copenhagen Ø, Denmark ; Centre for Star and Planet Formation, Geological Museum, Øster Voldgade 5-7, DK-1350 Copenhagen, Denmark
Wertz, Olivier ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS)
Alsubai, K. A.; Qatar Foundation, PO Box 5825, Doha, Qatar
Bozza, V.; Department of Physics, University of Salerno, I-84084-Fisciano (SA), Italy ; Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Napoli, Italy
Browne, P.; National Astronomical Observatories/Yunnan Observatory, Chinese Academy of Sciences, Kunming 650011, China
Dodds, P.; SUPA, University of St Andrews, School of Physics & Astronomy, North Haugh, St Andrews KY16 9SS, UK
Gu, S.-H.; National Astronomical Observatories/Yunnan Observatory, Chinese Academy of Sciences, Kunming 650011, China ; Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences, Kunming 650011, China
Harpsøe, K.; Niels Bohr Institute, University of Copenhagen, Juliane Maries vej 30, DK-2100 Copenhagen Ø, Denmark ; Centre for Star and Planet Formation, Geological Museum, Øster Voldgade 5-7, DK-1350 Copenhagen, Denmark
Henning, Th; Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany
Hundertmark, M.; SUPA, University of St Andrews, School of Physics & Astronomy, North Haugh, St Andrews KY16 9SS, UK
Jessen-Hansen, J.; Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
Kains, N.; European Southern Observatory, Karl-Schwarzschild-Straße 2, D-85748 Garching bei München, Germany
Kerins, E.; Jodrell Bank Centre for Astrophysics, University of Manchester, Oxford Road, Manchester M13 9PL, UK
Kjeldsen, H.; Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
Lund, M. N.; Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
Lundkvist, M.; Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
Madhusudhan, N.; Department of Physics and Department of Astronomy, Yale University, New Haven, CT 06511, USA
Mathiasen, M.; Niels Bohr Institute, University of Copenhagen, Juliane Maries vej 30, DK-2100 Copenhagen Ø, Denmark ; Centre for Star and Planet Formation, Geological Museum, Øster Voldgade 5-7, DK-1350 Copenhagen, Denmark
Penny, M. T.; Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210, USA
Prof, S.; Department of Physics, Sharif University of Technology, P. O. Box 11155-9161 Tehran, Iran
Rahvar, S.; Department of Physics, Sharif University of Technology, P. O. Box 11155-9161 Tehran, Iran
Sahu, K.; Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
Scarpetta, G.; Department of Physics, University of Salerno, I-84084-Fisciano (SA), Italy ; Istituto Internazionale per gli Alti Studi Scientifici (IIASS), I-84019 Vietri Sul Mare (SA), Italy ; Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Napoli, Italy
Snodgrass, C.; Max-Planck-Institute for Solar system Research, Max-Planck Str. 2, D-37191 Katlenburg-Lindau, Germany
