2024/03/26 by Yan, Dongdong, Guo, Jianheng, Seon, Kwang-il +3 · 1 citation
#Earth and Planetary Astrophysics (astro-ph.EP) #FOS: Physical sciences
paper · doi:10.48550/arxiv.2403.17325
This paper presents a hydrodynamic simulation that couples detailed non-local thermodynamic equilibrium (NLTE) calculations of the hydrogen and helium level populations to model the Hα and He 10830 transmission spectra of the hot Jupiter HAT-P-32b. A Monte Carlo simulation is applied to calculate the number of Lyα resonance scatterings, which is the main process for populating H(2). In the examined parameter space, only the models with H/He ≥ 99.5/0.5, (0.5 ∼ 3.0) times the fiducial value of F\rm XUV, βm = 0.16∼ 0.3, can explain the Hα and He 10830 lines simultaneously. We find a mass-loss rate of ∼ (1.0∼ 3.1) × 1013 g s-1, consistent with previous studies. Moreover, we find 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. The difference in metallicity between the lower and upper atmospheres is essential for future atmospheric characterisations.