New Constraints On Triton’s Atmosphere From The 6 October 2022 Stellar Occultation

The atmosphere of Triton was probed directly by observing a ground-based stellar occultation on 6 October 2022. This rare event yielded 23 positive light curves collected from 13 separate observation stations contributing to our campaign.

The significance of this event lies in its potential to directly validate the modest pressure fluctuation on Triton, a phenomenon not definitively verified by previous observations, including only five stellar occultations, and the Voyager 2 radio occultation in 1989. Using an approach consistent with a comparable study, we precisely determined a surface pressure of 14.07^+0.21−0.13 μbar in 2022.

This new pressure rules out any significant monotonic variation in pressure between 2017 and 2022 through direct observations, as it is in alignment with the 2017 value. Additionally, both the pressures in 2017 and 2022 align with the 1989 value.

This provides further support for the conclusion drawn from the previous volatile transport model simulation, which is consistent with the observed alignment between the pressures in 1989 and 2017; that is to say, the pressure fluctuation is modest.

Moreover, this conclusion suggests the existence of a northern polar cap extended down to at least 45^∘N−60^∘N and the presence of nitrogen between 30^∘S and 0^∘.

Ye Yuan, Chen Zhang, Fan Li, Jian Chen, Yanning Fu, Chunhai Bai, Xin Gao, Yong Wang, Tuhong Zhong, Yixing Gao, Liang Wang, Donghua Chen, Yixing Zhang, Yang Zhang, Wenpeng Xie, Shupi Zhang, Ding Liu, Jun Cao, Xiangdong Yin, Xiaojun Mo, Jing Liu, Xinru Han, Tong Liu, Yuqiang Chen, Zhendong Gao, Xiang Zeng, Guihua Niu, Xiansheng Zheng, Yuchen Lin, Peiyu Ye, Weitang Liang, Chengcheng Zhu, Zhiqiang Hu, Jianguo He, Wei Zhang, Yue Chen, Zhuo Cheng, Yang Zhang, Tianrui Sun, Chenyang Guo, Yue Lu, Jiajun Lin, Wei Tan, Jia Zhou, Jun Xu, Jun He, Jiahui Ye, Delai Li, Shuai Zhang, Qingyue Qu

Comments: Astronomy & Astrophysics, in press. 9 pages, 2 figures, 3 tables
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2403.09464 [astro-ph.EP] (or arXiv:2403.09464v1 [astro-ph.EP] for this version)
Related DOI:
https://doi.org/10.1051/0004-6361/202348460
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Submission history
From: Ye Yuan
[v1] Thu, 14 Mar 2024 15:04:17 UTC (9,110 KB)
https://arxiv.org/abs/2403.09464
Astrobiology