Planets and satellites: atmospheres; Planets and satellites: individual: WASP-189 b; Techniques: photometric; Exo-planets; Gas giant; Oblateness; Photometrics; Planet and satellite: individual: WASP-189 b; Planets and satellites: individual; Stellars; Systems architecture; Astronomy and Astrophysics; Space and Planetary Science; astro-ph.EP; astro-ph.SR
Abstract :
[en] Context. Gas giants orbiting close to hot and massive early-type stars can reach dayside temperatures that are comparable to those of the coldest stars. These aultra-hot Jupitersahave atmospheres made of ions and atomic species from molecular dissociation and feature strong day-to-night temperature gradients. Photometric observations at different orbital phases provide insights on the planetas atmospheric properties. Aims. We aim to analyse the photometric observations of WASP-189 acquired with the Characterising Exoplanet Satellite (CHEOPS) to derive constraints on the system architecture and the planetary atmosphere. Methods. We implemented a light-curve model suited for an asymmetric transit shape caused by the gravity-darkened photosphere of the fast-rotating host star. We also modelled the reflective and thermal components of the planetary flux, the effect of stellar oblateness and light-travel time on transit-eclipse timings, the stellar activity, and CHEOPS systematics. Results. From the asymmetric transit, we measure the size of the ultra-hot Jupiter WASP-189 b, Rp = 1.600a0.016+0.017aRJ, with a precision of 1%, and the true orbital obliquity of the planetary system, Ψp = 89.6 ± 1.2deg (polar orbit). We detect no significant hotspot offset from the phase curve and obtain an eclipse depth of δecl = 96.5a5.0+4.5appm, from which we derive an upper limit on the geometric albedo: Ag < 0.48. We also find that the eclipse depth can only be explained by thermal emission alone in the case of extremely inefficient energy redistribution. Finally, we attribute the photometric variability to the stellar rotation, either through superficial inhomogeneities or resonance couplings between the convective core and the radiative envelope. Conclusions. Based on the derived system architecture, we predict the eclipse depth in the upcoming Transiting Exoplanet Survey Satellite (TESS) observations to be up to ~165 ppm. High-precision detection of the eclipse in both CHEOPS and TESS passbands might help disentangle reflective and thermal contributions. We also expect the right ascension of the ascending node of the orbit to precess due to the perturbations induced by the stellar quadrupole moment J2 (oblateness).
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Deline, A.; Department of Astronomy, University of Geneva, Versoix, Switzerland
Hooton, M.J.; Physikalisches Institut, University of Bern, Bern, Switzerland
Lendl, Monika ; Université de Liège - ULiège > Département d'astrophysique, géophysique et océanographie (AGO) > Origines Cosmologiques et Astrophysiques (OrCa) ; Department of Astronomy, University of Geneva, Versoix, Switzerland
Morris, B.; Center for Space and Habitability, University of Bern, Bern, Switzerland
Salmon, Sébastien ; Université de Liège - ULiège > Département d'astrophysique, géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie ; Department of Astronomy, University of Geneva, Versoix, Switzerland
Olofsson, G.; Department of Astronomy, Stockholm University, AlbaNova University Center, Stockholm, Sweden
Broeg, C.; Physikalisches Institut, University of Bern, Bern, Switzerland ; Center for Space and Habitability, University of Bern, Bern, Switzerland
Ehrenreich, D.; Department of Astronomy, University of Geneva, Versoix, Switzerland
Beck, M.; Department of Astronomy, University of Geneva, Versoix, Switzerland
Brandeker, A.; Department of Astronomy, Stockholm University, AlbaNova University Center, Stockholm, Sweden
Hoyer, S.; Aix-Marseille Universite´, CNRS, CNES, Laboratoire daAstrophysique de Marseille, Marseille, France
Sulis, S.; Aix-Marseille Universite´, CNRS, CNES, Laboratoire daAstrophysique de Marseille, Marseille, France
Van Grootel, Valérie ; Université de Liège - ULiège > Unités de recherche interfacultaires > Space sciences, Technologies and Astrophysics Research (STAR)
Bourrier, V.; Department of Astronomy, University of Geneva, Versoix, Switzerland
Demangeon, O.; Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Porto, Portugal ; Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
Demory, B.-O.; Center for Space and Habitability, University of Bern, Bern, Switzerland
Heng, K.; Center for Space and Habitability, University of Bern, Bern, Switzerland ; Department of Physics, University of Warwick, Coventry, United Kingdom ; University Observatory Munich, Ludwig Maximilian University, Munich, Germany
Parviainen, H.; Instituto de Astrofísica de Canarias, La Laguna, Spain ; Departamento de Astrofísica, Universidad de La Laguna, La Laguna, Spain
Serrano, L.M.; Dipartimento di Fisica, Università degli Studi di Torino, Torino, Italy
Singh, V.; INAF, Osservatorio Astronomico di Padova, Padova, Italy
Bonfanti, Andrea ; Université de Liège - ULiège > Unités de recherche interfacultaires > Space sciences, Technologies and Astrophysics Research (STAR) ; Space Research Institute, Austrian Academy of Sciences, Graz, Austria
Fossati, L.; Space Research Institute, Austrian Academy of Sciences, Graz, Austria
Kitzmann, D.; Center for Space and Habitability, University of Bern, Bern, Switzerland
Sousa, S.G.; Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Porto, Portugal
Wilson, T.G.; Centre for Exoplanet Science, SUPA School of Physics and Astronomy, University of St Andrews, St Andrews, United Kingdom
Alibert, Y.; Physikalisches Institut, University of Bern, Bern, Switzerland
Alonso, R.; Instituto de Astrofísica de Canarias, La Laguna, Spain ; Departamento de Astrofísica, Universidad de La Laguna, La Laguna, Spain
Anglada, G.; Institut de Ciències de laEspai (ICE CSIC), Campus UAB, Barcelona, Spain
Bárczy, T.; Admatis, Miskolc, Hungary
Barrado Navascues, D.; Departamento de Astrofísica, Centro de Astrobiología (CSIC-INTA), ESAC campus, Spain
Barros, S.C.C.; Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Porto, Portugal ; Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
Baumjohann, W.; Space Research Institute, Austrian Academy of Sciences, Graz, Austria
Beck, T.; Physikalisches Institut, University of Bern, Bern, Switzerland
Bekkelien, A.; Department of Astronomy, University of Geneva, Versoix, Switzerland
Benz, W.; Physikalisches Institut, University of Bern, Bern, Switzerland ; Center for Space and Habitability, University of Bern, Bern, Switzerland
Billot, N.; Department of Astronomy, University of Geneva, Versoix, Switzerland
Bonfils, X.; Université Grenoble Alpes, CNRS, Institut de Planétologie et daAstrophysique de Grenoble, Grenoble, France
Cabrera, J.; Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany
Charnoz, S.; Université de Paris, Institut de Physique du Globe de Paris, CNRS, Paris, France
Collier Cameron, A.; Centre for Exoplanet Science, SUPA School of Physics and Astronomy, University of St Andrews, St Andrews, United Kingdom
Corral Van Damme, C.; European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Noordwijk, Netherlands
Csizmadia, Sz.; Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany
Davies, M.B.; Centre for Mathematical Sciences, Lund University, Lund, Sweden
Deleuil, M.; Aix-Marseille Universite´, CNRS, CNES, Laboratoire daAstrophysique de Marseille, Marseille, France
De Roche, T.; Physikalisches Institut, University of Bern, Bern, Switzerland
Erikson, A.; Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany
Fortier, A.; Physikalisches Institut, University of Bern, Bern, Switzerland ; Center for Space and Habitability, University of Bern, Bern, Switzerland
Fridlund, M.; Leiden Observatory, University of Leiden, Leiden, Netherlands ; Department of Space, Earth and Environment, Chalmers University of Technology, Onsala, Sweden
Futyan, D.; Department of Astronomy, University of Geneva, Versoix, Switzerland
Gandolfi, D.; Dipartimento di Fisica, Università degli Studi di Torino, Torino, Italy
Güdel, M.; Department of Astrophysics, University of Vienna, Vienna, Austria
Gutermann, P.; Aix-Marseille Universite´, CNRS, CNES, Laboratoire daAstrophysique de Marseille, Marseille, France ; Division Technique, Institut National des Sciences de laUnivers (INSU), La Seyne-sur-Mer, France
Hasiba, J.; Space Research Institute, Austrian Academy of Sciences, Graz, Austria
Isaak, K.G.; European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Noordwijk, Netherlands
Kiss, L.; Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Budapest, Hungary
Laskar, J.; IMCCE, UMR8028 CNRS, Observatoire de Paris, PSL Université, Sorbonne Université, Paris, France
Lecavelier Des Etangs, A.; Institut daastrophysique de Paris, UMR7095 CNRS, Université Pierre and Marie Curie, Paris, France
Lovis, C.; Department of Astronomy, University of Geneva, Versoix, Switzerland
Magrin, D.; INAF, Osservatorio Astronomico di Padova, Padova, Italy
Maxted, P.F.L.; Astrophysics Group, Keele University, Staffordshire, United Kingdom
Munari, M.; INAF, Osservatorio Astrofisico di Catania, Catania, Italy
Nascimbeni, V.; INAF, Osservatorio Astronomico di Padova, Padova, Italy
Ottensamer, R.; Department of Astrophysics, University of Vienna, Vienna, Austria
Pagano, I.; INAF, Osservatorio Astrofisico di Catania, Catania, Italy
Pallé, E.; Instituto de Astrofísica de Canarias, La Laguna, Spain
Peter, G.; Institute of Optical Sensor Systems, German Aerospace Center (DLR), Berlin, Germany
Piotto, G.; INAF, Osservatorio Astronomico di Padova, Padova, Italy ; Dipartimento di Fisica e Astronomia Galileo Galileia, Università degli Studi di Padova, Padova, Italy
Pollacco, D.; Department of Physics, University of Warwick, Coventry, United Kingdom
Queloz, D.; Cavendish Laboratory, Cambridge, United Kingdom ; Department of Physics, ETH Zürich, Zürich, Switzerland
Ragazzoni, R.; INAF, Osservatorio Astronomico di Padova, Padova, Italy ; Dipartimento di Fisica e Astronomia Galileo Galileia, Università degli Studi di Padova, Padova, Italy
Rando, N.; European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Noordwijk, Netherlands
Rauer, H.; Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany ; Center for Astronomy and Astrophysics, Technical University Berlin, Berlin, Germany ; Institut für Geologische Wissenschaften, Freie Universität Berlin, Berlin, Germany
Ribas, I.; Institut de Ciències de laEspai (ICE CSIC), Campus UAB, Barcelona, Spain ; Institut daEstudis Espacials de Catalunya (IEEC), Barcelona, Spain
Santos, N.C.; Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Porto, Portugal ; Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
Scandariato, G.; INAF, Osservatorio Astrofisico di Catania, Catania, Italy
Ségransan, D.; Department of Astronomy, University of Geneva, Versoix, Switzerland
Simon, A.E.; Physikalisches Institut, University of Bern, Bern, Switzerland
Smith, A.M.S.; Institute of Planetary Research, German Aerospace Center (DLR), Berlin, Germany
Steller, M.; Space Research Institute, Austrian Academy of Sciences, Graz, Austria
Szabó, Gy. M.; ELTE Eötvös Loránd University, Gothard Astrophysical Observatory, Szombathely, Hungary ; MTA-ELTE Exoplanet Research Group, Szombathely, Hungary
Thomas, N.; Physikalisches Institut, University of Bern, Bern, Switzerland
Udry, S.; Department of Astronomy, University of Geneva, Versoix, Switzerland
Walter, I.; Institute of Optical Sensor Systems, German Aerospace Center (DLR), Berlin, Germany
Walton, N.; Institute of Astronomy, University of Cambridge, Cambridge, United Kingdom
Acknowledgements. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (project FOUR ACES, grant agreement No. 724427). It has also been carried out in the frame of the National Centre for Competence in Research “PlanetS” supported by the Swiss National Science Foundation (SNSF). A.De. acknowledges the financial support of the SNSF. M.J.Ho. and Y.Al. acknowledge the support of the Swiss National Fund under grant 200020_172746. M.Le. acknowledges support from the Swiss National Science Foundation under grant No. PCEFP2_194576. S.Sa. has received funding from the European Research Council (ERC) under the European Unions Horizon 2020 research and innovation programme (project STAREX, grant agreement No. 833925). D.Eh. acknowledges support from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (project FOUR ACES, grant agreement No. 724427). A.Br. was supported by the SNSA. S.Ho. gratefully acknowledges CNES funding through the grant 837319. V.V.Gr. is an F.R.S-FNRS Research Associate. V.Bo. acknowledges support from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (project FOUR ACES, grant agreement No. 724427; project SPICE DUNE, grant agreement No. 947634, project SCORE, grant agreement no. 851555). O.De. acknowledges support by FCT - Fundação para a Ciência e a Tecnologia through national funds and by FEDER through COMPETE2020 - Programa Operacional Competitividade e Internacionalizacão by these grants: UID/FIS/04434/2019, UIDB/04434/2020, UIDP/04434/2020, PTDC/FIS-AST/32113/2017 and POCI-01-0145-FEDER-032113, PTDC/FIS-AST/28953/2017 and POCI-01-0145-FEDER-028953, PTDC/FIS-AST/28987/2017 and POCI-01-0145-FEDER-028987, O.De. is supported in the form of work contract (DL 57/2016/CP1364/CT0004) funded by national funds through FCT. B.-O.De. acknowledges support from the Swiss National Science Foundation (PP00P2-190080). L.M.Se. gratefully acknowledges financial support from the CRT foundation under Grant No. 2018.2323 “Gaseous or rocky? Unveiling the nature of small worlds”. S.G.So. acknowledges support from FCT through FCT contract No. CEECIND/00826/2018 and POPH/FSE (EC). T.G.Wi. and A.C.Ca. acknowledge support from STFC consolidated grant numbers ST/R000824/1 and ST/V000861/1, and UKSA grant ST/R003203/1. R.Al. acknowledges support from the Spanish Ministry of Science and Innovation and the European Regional Development Fund through grants ESP2016-80435-C2-1-R, ESP2016-80435-C2-2-R, PGC2018-098153-B-C33, PGC2018-098153-B-C31, ESP2017-87676-C5-1-R, MDM-2017-0737 Unidad de Excelencia Maria de Maeztu-Centro de Astrobiologí-a (INTA-CSIC), as well as the support of the Generalitat de Catalunya/CERCA programme. The MOC activities have been supported by the ESA contract No. 4000124370. S.C.C.Ba. acknowledges support from FCT through FCT contracts No. IF/01312/2014/CP1215/CT0004. X.Bo. acknowledges his role as ESA-appointed CHEOPS science team member. M.De. acknowledges support by the CNES. The Belgian participation to CHEOPS has been supported by the Belgian Federal Science Policy Office (BELSPO) in the framework of the PRODEX Program, and by the University of Liège through an ARC grant for Concerted Research Actions financed by the Wallonia-Brussels Federation. L.De. is an F.R.S.-FNRS Postdoctoral Researcher. M.Fr. gratefully acknowledges the support of the Swedish National Space Agency (DNR 65/19, 174/18). D.Ga. gratefully acknowledges financial support from the CRT foundation under Grant No. 2018.2323 “Gaseous or rocky? Unveiling the nature of small worlds”. M.Gi. is an F.R.S.-FNRS Senior Research Associate. K.G.Is. is the ESA CHEOPS Project Scientist and is responsible for the ESA CHEOPS Guest Observers Programme. She does not participate in, or contribute to, the definition of the Guaranteed Time Programme of the CHEOPS mission through which observations described in this paper have been taken, nor to any aspect of target selection for the programme. J.La. acknowledges granted access to the HPC resources of MesoPSL financed by the Region Ile de France and the project Equip@Meso (reference ANR-10-EQPX-29-01) of the programme Investissements d’Avenir supervised by the Agence Nationale pour la Recherche. P.Ma. acknowledges support from STFC research grant number ST/M001040/1. D.Qu. acknowledges partial support by a grant from the Simons Foundation (PI Queloz, grant number 327127). I.Ri. acknowledges support from the Spanish Ministry of Science and Innovation and the European Regional Development Fund through grant PGC2018-098153-B-C33, as well as the support of the Generalitat de Catalunya/CERCA programme. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. We thank the referee for the insightful comments that helped improve the quality of this work.
Commentary :
25 pages, 16 figures, 5 tables (including the appendix); published in
A&A
