| Issue |
A&A
Volume 678, October 2023
|
|
|---|---|---|
| Article Number | A150 | |
| Number of page(s) | 10 | |
| Section | Planets and planetary systems | |
| DOI | https://doi.org/10.1051/0004-6361/202347160 | |
| Published online | 17 October 2023 | |
Detection of atmospheric species and dynamics in the bloated hot Jupiter WASP-172 b with ESPRESSO★
1
European Southern Observatory,
Alonso de Córdova 3107, Vitacura,
Región Metropolitana, Chile
e-mail: jseidel@eso.org
2
Lund Observatory, Division of Astrophysics, Department of Physics, Lund University,
Box 43,
221 00
Lund, Sweden
3
Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University,
Ny Munkegade 120,
8000
Aarhus C, Denmark
4
Chalmers University of Technology, Department of Space, Earth and Environment,
Chalmersplatsen 4,
412 93
Gothenburg, Sweden
5
Astronomy Department and Center for Integrative Planetary Science, University of California Berkeley,
501 Campbell Hall,
Berkeley, CA
94720, USA
Received:
12
June
2023
Accepted:
25
August
2023
Context. The population of strongly irradiated Jupiter-sized planets has no equivalent in the Solar System. It is characterised by strongly bloated atmospheres and large atmospheric scale heights. Recent space-based observations of SO2 photochemistry have demonstrated the knowledge that can be gained about Earth’s uniqueness from detailed atmospheric studies of these unusual planets.
Aims. Here we explore the atmosphere of WASP-172 b, a planet similar in terms of temperature and bloating to the recently studied HD 149026 b. We characterise the atmospheric composition and subsequently the atmospheric dynamics of this prime target.
Methods. We observed a particular transit of WASP-172 b in front of its host star with ESO’s ESPRESSO spectrograph and analysed the spectra obtained before, during, and after transit.
Results. We detect the absorption of starlight by WASP-172 b’s atmosphere by sodium (5.6σ) and hydrogen (19.5σ) and obtained a tentative detection of iron (4.1σ). We detect strong – yet varying – blueshifts, relative to the planetary rest frame, of all of these absorption features. This allows for a preliminary study of the atmospheric dynamics of WASP-172 b.
Conclusions. With only one transit, we were able to detect a wide variety of species that clearly track different atmospheric layers with possible jets. WASP-172 b is a prime follow-up target for a more in-depth characterisation with both ground- and space-based observatories. If the detection of Fe is confirmed, this may suggest that radius inflation is an important determinant for the detectability of Fe in hot Jupiters, as several non-detections of Fe have been published for planets that are hotter but less inflated than WASP-172 b.
Key words: planets and satellites: atmospheres / planets and satellites: individual: WASP-172b / techniques: spectroscopic / methods: data analysis / line: profiles
© The Authors 2023
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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