Constraints on the structure and seasonal variations of Triton’s atmosphere from the 5 October 2017 stellar occultation and previous observations
A stellar occultation by Triton in October 2017 gives new constraints on the structure of its atmosphere and on how it changes with the seasons.
What was found
- The surface pressure is about 14.1 µbar, consistent with the value measured by Voyager 2 in 1989, so no significant change is found between those epochs.
- The 2017 density profiles match the Voyager 2 radio profile where they overlap. The temperature profiles show a cooling turning point in the deepest layers, and the lower atmosphere appears convectively stable.
- The central flash, which probes the atmosphere about 8 km above the surface, is consistent with a spherical shape. The upper limit on its oblateness implies equatorial winds of roughly 63 m/s or less (1σ).
- Volatile transport modelling suggests that the pressure rise of the 1990s is debatable given the sparse data, and that a northern nitrogen ice cap helps to explain the observed pressures.
This summary is written for a general audience. The paper has the full details.
Cite this paper
Marques Oliveira, J., et al. 2022, A&A, 659, A136, doi:10.1051/0004-6361/202141443
@article{marquesoliveira2022,
author = {Marques Oliveira, J. and others},
title = {{Constraints on the structure and seasonal variations of Triton’s atmosphere from the 5 October 2017 stellar occultation and previous observations}},
journal = {Astronomy & Astrophysics},
year = {2022},
volume = {659},
pages = {A136},
doi = {10.1051/0004-6361/202141443},
eprint = {2201.10450},
archivePrefix = {arXiv}
}