WASP-193b: An extremely low-density super-Neptune

Barkaoui, Khalid; J. Pozuelos, Francisco; Hellier, Coel; Smalley, Barry; D. Nielsen, Louise; Dorn, Caroline; Niraula, Prajwal; Gillon, Michaël; de Wit, Julien; Helled, Ravit; Müller, Simon; Jehin, Emmanuel; Demory, Brice-Olivier; Van Grootel, V.; Soubkiou, Abderahmane; Ghachoui, Mourad; R. Anderson, David.; Benkhaldoun, Zouhair; Bouchy, Francois; Burdanov, Artem; Delrez, Laetitia; Ducrot, Elsa; Garcia, Lionel; Jabiri, Abdelhadi; Lendl, Monika; F. L. Maxted, Pierre; A. Murray, Catriona; Pihlmann Pedersen, Peter; Queloz, Didier; Sebastian, Daniel; Turner, Oliver; Udry, Stephane; Timmermans, Mathilde; H. M. J. Triaud, Amaury; G. West, Richard

WASP-193b: An extremely low-density super-Neptune

Barkaoui, Khalid; J. Pozuelos, Francisco; Hellier, Coel; Smalley, Barry; D. Nielsen, Louise; Dorn, Caroline; Niraula, Prajwal; Gillon, Michaël; de Wit, Julien; Helled, Ravit; Müller, Simon; Jehin, Emmanuel; Demory, Brice-Olivier; Van Grootel, V.; Soubkiou, Abderahmane; Ghachoui, Mourad; R. Anderson, David.; Benkhaldoun, Zouhair; Bouchy, Francois; Burdanov, Artem; Delrez, Laetitia; Ducrot, Elsa; Garcia, Lionel; Jabiri, Abdelhadi; Lendl, Monika; F. L. Maxted, Pierre; A. Murray, Catriona; Pihlmann Pedersen, Peter; Queloz, Didier; Sebastian, Daniel; Turner, Oliver; Udry, Stephane; Timmermans, Mathilde; H. M. J. Triaud, Amaury; G. West, Richard

Authors

Khalid Barkaoui

Francisco J. Pozuelos

Coel Hellier

Barry Smalley b.smalley@keele.ac.uk

Louise D. Nielsen

Caroline Dorn

Prajwal Niraula

Michaël Gillon

Julien de Wit

Ravit Helled

Simon Müller

Emmanuel Jehin

Brice-Olivier Demory

V. Van Grootel

Abderahmane Soubkiou

Mourad Ghachoui

David. R. Anderson

Zouhair Benkhaldoun

Francois Bouchy

Artem Burdanov

Laetitia Delrez

Elsa Ducrot

Lionel Garcia

Abdelhadi Jabiri

Monika Lendl

Pierre Maxted p.maxted@keele.ac.uk

Catriona A. Murray

Peter Pihlmann Pedersen

Didier Queloz

Daniel Sebastian

Oliver Turner

Stephane Udry

Mathilde Timmermans

Amaury H. M. J. Triaud

Richard G. West

Abstract

Gas giants transiting bright nearby stars are stepping stones for our understanding of planetary system formation and evolution mechanisms. This paper presents a particularly interesting new specimen of this kind of exoplanet discovered by the WASP-South transit survey, WASP-193b. This planet completes an orbit around its Vmag = 12.2 F9 main-sequence host star every 6.25 d. Our analyses found that WASP-193b has a mass of Mp = 0.139 +/- 0.029 M_Jup and a radius of Rp = 1.464 +/- 0.058 R_ Jup, translating into an extremely low density of rhop = 0.059 +\- 0.014 g/cm^3. The planet was confirmed photometrically by the 0.6-m TRAPPIST-South, the 1.0-m SPECULOOS-South telescopes, and the TESS mission, and spectroscopically by the ESO-3.6-m/HARPS and Euler-1.2-m/CORALIE spectrographs. The combination of its large transit depth (dF~1.4 %), its extremely-low density, its high-equilibrium temperature (Teq = 1254 +/- 31 K), and the infrared brightness of its host star (magnitude Kmag=10.7) makes WASP-193b an exquisite target for characterization by transmission spectroscopy (transmission spectroscopy metric: TSM ~ 600). One single JWST transit observation would yield detailed insights into its atmospheric properties and planetary mass, within ~0.1 dex and ~1% (vs ~20% currently with radial velocity data) respectively.

Citation

Barkaoui, K., J. Pozuelos, F., Hellier, C., Smalley, B., D. Nielsen, L., Dorn, C., …G. West, R. WASP-193b: An extremely low-density super-Neptune. arXiv,

Journal Article Type	Article
Deposit Date	Aug 31, 2023
Publicly Available Date	Aug 31, 2023
Print ISSN	2331-8422
Publisher	Cornell University
Peer Reviewed	Not Peer Reviewed
Keywords	Earth and Planetary Astrophysics
Publisher URL	https://arxiv.org/abs/2307.08350#:~:text=This%20planet%20completes%20an%20orbit,0.014%20g%2Fcm%5E3.