[en] Gas giants transiting bright nearby stars provide crucial insights into planetary system formation and evolution mechanisms. Most of these planets show certain average characteristics, serving as benchmarks for our understanding of planetary systems. However, outliers like the planet we present in this study, WASP-193 b, offer unique opportunities to explore unconventional formation and evolution processes. This planet completes an orbit around its V-band-magnitude 12.2 F9 main-sequence host star every 6.25 days. Our analyses found that WASP-193 b has a mass of 0.139 ± 0.029 MJ and a radius of 1.464 ± 0.058 RJ, translating into an extremely low density of 0.059 ± 0.014g cm^−3, at least one order of magnitude less than standard gas giants like Jupiter. Typical gas giants such as Jupiter have densities that range between 0.2 g cm^−3 and 2 g cm^−3. The combination of its large transit depth (1.4%), extremely low density, high-equilibrium temperature (1,254 ± 31 K) and the infrared brightness of its host star (K-band magnitude 10.7) makes WASP-193 b an exquisite target for characterization by transmission spectroscopy (transmission spectroscopy metric ~600). One single JWST transit observation would yield detailed insights into its atmospheric properties and planetary mass, providing a unique window to explore the mechanisms behind its exceptionally low density and shed light on giant planets' diverse nature.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Barkaoui, Khalid ; Université de Liège - ULiège > Département d'astrophysique, géophysique et océanographie (AGO) > Exoplanets in Transit: Identification and Characterization
Pozuelos, Francisco J.; University of Liege, Belgium, Institute of Astrophysics of Andalusia
Hellier, Coel; Keele University, Department of Physics and Astrophysics
Smalley, Barry; Keele University, Department of Physics and Astrophysics
Nielsen, Louise D.; University of Geneva, Astronomical Observatory, European Southern Observatory, Germany
Niraula, Prajwal; MIT, Department of Earth and Planetary Science
Gillon, Michaël ; Université de Liège - ULiège > Département d'astrophysique, géophysique et océanographie (AGO)
de Wit, Julien; MIT, Department of Earth and Planetary Science
Müller, Simon; Department of Astrophysics, University of Zürich, Zurich, Switzerland
Dorn, Caroline; Department of Astrophysics, University of Zürich, Zurich, Switzerland
Helled, Ravit; Department of Astrophysics, University of Zürich, Zurich, Switzerland
Jehin, Emmanuel ; Université de Liège - ULiège > Unités de recherche interfacultaires > Space sciences, Technologies and Astrophysics Research (STAR)
Demory, Brice-Olivier; University of Bern, Physics Institute
Van Grootel, Valérie ; Université de Liège - ULiège > Département d'astrophysique, géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie
Soubkiou, Abderahmane; University Cadi Ayyad, Morocco, -
Anderson, David. R.; University of Warwick, Department of Physics
Benkhaldoun, Zouhair; University Cadi Ayyad, Morocco
Bouchy, Francois; University of Geneva, Astronomical Observatory
Burdanov, Artem; MIT, Department of Earth and Planetary Science
Delrez, Laetitia; University of Liege, Belgium, University of Liege, Laboratory of Planetary and Atmospheric Physics
Ducrot, Elsa; LESIA, Observatoire de Paris, CNRS, Université Paris Diderot, Université Pierre et Marie Curie, Paris, France, Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM, Paris, France
Garcia, Lionel; University of Liege, Belgium, Center for Computational Astrophysics, Flatiron Institute, New York
Jabiri, Abdelhadi; University Cadi Ayyad, Morocco
Lendl, Monika; University of Geneva, Astronomical Observatory
Maxted, Pierre F. L.; Keele University, Department of Physics and Astrophysics
Murray, Catriona A.; University of Colorado, Boulder, Department of Astrophysical and Planetary Sciences
Pedersen, Peter Pihlmann; University of Cambridge, Institute of Astronomy
Queloz, Didier; University of Geneva, Astronomical Observatory, University of Cambridge, Institute of Astronomy
Sebastian, Daniel; University of Birmingham, School of Physics and Astronomy
Turner, Oliver; University of Geneva, Astronomical Observatory, -
Udry, Stephane; University of Geneva, Astronomical Observatory
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