techniques: photometric; stars: fundamental parameters; stars: individual: WASP-52; planetary systems
Abstract :
[en] We report 13 high-precision light curves of eight transits of the exoplanet WASP-52 b, obtained by using four medium-class telescopes, through different filters, and adopting the defocussing technique. One transit was recorded simultaneously from two different observatories and another one from the same site but with two different instruments, including a multiband camera. Anomalies were clearly detected in five light curves and modelled as star-spots occulted by the planet during the transit events. We fitted the clean light curves with the JKTEBOP code, and those with the anomalies with the PRISM+GEMC codes in order to simultaneously model the photometric parameters of the transits and the position, size and contrast of each star-spot. We used these new light curves and some from the literature to revise the physical properties of the WASP-52 system. Star-spots with similar characteristics were detected in four transits over a period of 43 d. In the hypothesis that we are dealing with the same star-spot, periodically occulted by the transiting planet, we estimated the projected orbital obliquity of WASP-52 b to be λ = 3.8° ± 8.4°. We also determined the true orbital obliquity, ψ = 20° ± 50°, which is, although very uncertain, the first measurement of ψ purely from star-spot crossings. We finally assembled an optical transmission spectrum of the planet and searched for variations of its radius as a function of wavelength. Our analysis suggests a flat transmission spectrum within the experimental uncertainties.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Mancini, L.; Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany ; INAF - Osservatorio Astrofisico di Torino, via Osservatorio 20, I-10025 Pino Torinese, Italy ; Dipartimento di Fisica, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 - Roma, Italy
Southworth, J.; Astrophysics Group, Keele University, Keele ST5 5BG, UK
Raia, G.; INAF - Osservatorio Astronomico di Capodimonte, via Moiariello 16, I-80131 Naples, Italy
Tregloan-Reed, J.; NASA Ames Research Center, Moffett Field, CA 94035, USA
Mollière, P.; Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany
Bozza, V.; Dipartimenti di Fisica `E. R. Caianiello', Università di Salerno, Via Giovanni Paolo II 132, I-84084 Fisciano (SA), Italy ; Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Via Cintia, I-80126 Naples, Italy
Bretton, M.; Observatoire des Baronnies Provençales, Le Mas des Grès, Route de Nyons, F-05150 Moydans, France
Bruni, I.; INAF - Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna, Italy
Ciceri, S.; Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany
D'Ago, G.; Dipartimenti di Fisica `E. R. Caianiello', Università di Salerno, Via Giovanni Paolo II 132, I-84084 Fisciano (SA), Italy ; Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Via Cintia, I-80126 Naples, Italy ; International Institute for Advanced Scientific Studies (IIASS), Via G. Pellegrino 19, I-84019 Vietri sul Mare (SA), Italy
Dominik, M.; SUPA, School of Physics & Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS, UK
Hinse, T. C.; Korea Astronomy & Space Science Institute, 776 Daedukdae-ro, Yuseong-gu, 305-348 Daejeon, Republic of Korea
Hundertmark, M.; Niels Bohr Institute & Centre for Star and Planet Formation, University of Copenhagen, Øster Voldgade 5, DK-1350 Copenhagen, Denmark
Jørgensen, U. G.; Niels Bohr Institute & Centre for Star and Planet Formation, University of Copenhagen, Øster Voldgade 5, DK-1350 Copenhagen, Denmark
Korhonen, H.; Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen, Denmark ; Niels Bohr Institute & Centre for Star and Planet Formation, University of Copenhagen, Øster Voldgade 5, DK-1350 Copenhagen, Denmark ; Finnish Centre for Astronomy with ESO (FINCA), Väisäläntie 20, FI-21500 Piikkiö, Finland
Rabus, M.; Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 7820436 Macul, Santiago, Chile ; Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany
Rahvar, S.; Department of Physics, Sharif University of Technology, PO Box 11155-9161 Tehran, Iran
Starkey, D.; SUPA, School of Physics & Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS, UK
Calchi Novati, S.; Dipartimenti di Fisica `E. R. Caianiello', Università di Salerno, Via Giovanni Paolo II 132, I-84084 Fisciano (SA), Italy ; NASA Exoplanet Science Institute, MS 100-22, California Institute of Technology, Pasadena, CA 91125, USA ; International Institute for Advanced Scientific Studies (IIASS), Via G. Pellegrino 19, I-84019 Vietri sul Mare (SA), Italy
Figuera Jaimes, R.; SUPA, School of Physics & Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS, UK ; European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei München, Germany
Henning, Th; Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany
Juncher, D.; Niels Bohr Institute & Centre for Star and Planet Formation, University of Copenhagen, Øster Voldgade 5, DK-1350 Copenhagen, Denmark
Haugbølle, T.; Niels Bohr Institute & Centre for Star and Planet Formation, University of Copenhagen, Øster Voldgade 5, DK-1350 Copenhagen, Denmark
Kains, N.; Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
Popovas, A.; Niels Bohr Institute & Centre for Star and Planet Formation, University of Copenhagen, Øster Voldgade 5, DK-1350 Copenhagen, Denmark
Schmidt, R. W.; Astronomisches Rechen-Institut, Zentrum für Astronomie, Universität Heidelberg, Mönchhofstrasse 12-14, D-69120 Heidelberg, Germany
Skottfelt, J.; Department of Physical Sciences, Centre for Electronic Imaging, The Open University, Milton Keynes MK7 6AA, UK ; Niels Bohr Institute & Centre for Star and Planet Formation, University of Copenhagen, Øster Voldgade 5, DK-1350 Copenhagen, Denmark
Snodgrass, C.; Planetary and Space Science, Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA, UK
Surdej, Jean ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Département d'astrophys., géophysique et océanographie (AGO)
Wertz, O.; Institut d'Astrophysique et de Géophysique, Allée du 6 Août 19c, Sart Tilman, B-4000 Liège, Belgium)
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