The capability of CSST in characterizing planetary atmospheres. I. transmission spectroscopy of hot Jupiters

Zibo Liu; Wei Wang; Meng Zhai; Jinpeng Wang; Qinglin Ouyang; Fei Yan; Guo Chen; Dongdong Ni; Yong Zhao; Yujuan Liu; Fei Zhao; Gang Zhao

arXiv · 2606.16452

The capability of CSST in characterizing planetary atmospheres. I. transmission spectroscopy of hot Jupiters

Zibo Liu·Wei Wang·Meng Zhai·Jinpeng Wang·Qinglin Ouyang·Fei Yan·Guo Chen·Dongdong Ni·Yong Zhao·Yujuan Liu·Fei Zhao·Gang Zhao

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Abstract

Transmission spectroscopy has become a primary tool for probing exoplanetary atmospheres, enabling constraints on their chemical compositions and providing limited information on their thermal properties. We assess the potential of the upcoming Chinese Space Station Telescope (CSST) for exoplanet atmospheric characterization through transmission spectroscopy. Theoretical spectra of hot gas planets are generated and used to simulate slitless spectroscopic observations with the CSST across the ultraviolet-to-near-infrared range. Atmospheric retrievals performed on the simulated data are compared with the input models to assess the robustness and accuracy of parameter determinations. We find that multi-band observations across three wavelength channels, each with two transits can place meaningful constraints on key atmospheric parameters. For multi-band observations that account for correlated (red) noise, future CSST observations are expected to achieve constraints that are comparable to, or in some cases slightly weaker than, those of the Hubble Space Telescope (HST), depending on the noise level and observing strategy. We conclude that CSST will provide unique and complementary constraints on the chemical compositions and physical properties of exoplanetary atmospheres, particularly for atomic species, metal-bearing molecules, and scattering processes accessible in the UV and optical, thereby complementing JWST's infrared sensitivity to molecular species.

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Zibo Liu, Wei Wang, Meng Zhai, Jinpeng Wang, Qinglin Ouyang, Fei Yan, Guo Chen, Dongdong Ni, Yong Zhao, Yujuan Liu, Fei Zhao, Gang Zhao. 2026-06-15. The capability of CSST in characterizing planetary atmospheres. I. transmission spectroscopy of hot Jupiters. https://arxiv.org/abs/2606.16452

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