Constraints on Triton atmospheric evolution from occultations: 1989-2022 ...

• Main Authors: Sicardy, B., Tej, A., Gomes-Junior, A. R., Romanov, F. D., Bertrand, T., Ashok, N. M., Lellouch, E., Morgado, B. E., Assafin, M., Desmars, J., Camargo, J. I. B., Kilic, Y., Ortiz, J. L., Vieira-Martins, R., Braga-Ribas, F., Ninan, J. P., Bhatt, B. C., Kumar, S. Pramod, Swain, V., Sharma, S., Saha, A., Ojha, D. K., Pawar, G., Deshmukh, S., Deshpande, A., Ganesh, S., Jain, J. K., Mathew, S. K., Kumar, H., Bhalerao, V., Anupama, G. C., Barway, S., Brandeker, A., Floren, H. G., Olofsson, G., Bruno, G., Mao, Y. M., Ye, R. H., Zou, Q. Y., Sun, Y. K., Shen, Y. Y., Zhao, J. Y., Grishin, D. N., Romanova, L. V., Marchis, F., Fukui, K., Kukita, R., Benedetti-Rossi, G., Santos-Sanz, P., Dhyani, N.
• Format: Report
• Language: unknown
• Published: arXiv 2024
• Subjects: Earth and Planetary Astrophysics astro-ph.EP; FOS Physical sciences; South Pole; Triton; South pole
• Online Access: https://dx.doi.org/10.48550/arxiv.2402.02476; https://arxiv.org/abs/2402.02476

Context - Around the year 2000, Triton's south pole experienced an extreme summer solstice that occurs every about 650 years, when the subsolar latitude reached about 50°. Bracketing this epoch, a few occultations probed Triton's atmosphere in 1989, 1995, 1997, 2008 and 2017. A recent ground-based stellar occultation observed on 6 October 2022 provides a new measurement of Triton's atmospheric pressure which is presented here. Aims- The goal is to constrain the Volatile Transport Models (VTMs) of Triton's atmosphere that is basically in vapor pressure equilibrium with the nitrogen ice at its surface. Methods - Fits to the occultation light curves yield Triton's atmospheric pressure at the reference radius 1400 km, from which the surface pressure is induced. Results - The fits provide a pressure p_1400= 1.211 +/- 0.039 microbar at radius 1400 km (47 km altitude), from which a surface pressure of p_surf= 14.54 +/- 0.47 microbar is induced (1-sigma error bars). To within error bars, this is identical to the ... : 8 pages, 4 figures, accepted for publication in Astronomy and Astrophysics ...