Issue |
A&A
Volume 686, June 2024
|
|
---|---|---|
Article Number | A208 | |
Number of page(s) | 13 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361/202348210 | |
Published online | 13 June 2024 |
A possibly solar metallicity atmosphere escaping from HAT-P-32b revealed by Hα and He absorption
1
Yunnan Observatories, Chinese Academy of Sciences,
PO Box 110,
Kunming
650216,
PR
China
e-mail: yand@ynao.ac.cn
2
Key Laboratory for the Structure and Evolution of Celestial Objects, CAS,
Kunming
650216,
PR
China
3
International Centre of Supernovae, Yunnan Key Laboratory,
Kunming
650216,
PR
China
4
School of Astronomy and Space Science, University of Chinese Academy of Sciences,
Beijing,
PR
China
5
Korea Astronomy & Space Science Institute,
776 Daedeokdae-ro, Yuseong-gu,
Daejeon
34055,
Republic of Korea
6
Astronomy and Space Science Major, University of Science and Technology,
217, Gajeong-ro, Yuseong-gu,
Daejeon
34113,
Republic of Korea
7
Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n,
18008
Granada,
Spain
8
Thüringer Landessternwarte Tautenburg,
Sternwarte 5,
07778
Tautenburg,
Germany
Received:
9
October
2023
Accepted:
25
March
2024
This paper presents a hydrodynamic simulation that couples detailed non-local thermodynamic equilibrium (NLTE) calculations of the helium and hydrogen level populations to model the Hα and He 10830 transmission spectra of the hot Jupiter HAT-P-32b. A Monte Carlo simulation was applied to calculate the number of Lyα resonance scatterings, which is the main process for populating H(2). In the examined parameter space, only models with H/He ≥ 99.5/0.5, (0.5 ~ 3.0) times the fiducial value of FXUV, and spectral index βm = (0.16 ~ 0.3), can explain the Hα and He 10830 lines simultaneously. We found a mass-loss rate of ~(1.0 ~ 3.1) × 1013 g s−1, consistent with previous studies. Moreover, we found that the stellar Lyα flux should be as high as 4 × 105 erg cm−2 s−1, indicating high stellar activity during the observation epoch of the two absorption lines. Despite the fact that the metallicity in the lower atmosphere of HAT-P-32b may be super-solar, our simulations tentatively suggest it is close to solar in the upper atmosphere. Understanding the difference in metallicity between the lower and upper atmospheres is essential for future atmospheric characterisations.
Key words: hydrodynamics / radiative transfer / methods: numerical / planets and satellites: atmospheres / planets and satellites: composition / planets and satellites: individual: HAT-P-32b
© The Authors 2024
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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