2,3,3,5,6,- 1Observatoire de Paris, LIRA, Meudon, France (emmanuel.lellouch@obspm.fr)
- 2Instituto de Astrofisica de Andalucia, Granada, Spain
- 3Space Telescope Science Institute, Baltimore, USA
- 4Southwestern Research Institude, Boulder, USA
- 5Jet Propulsion Laboratory, California Institude of Technology, USA
- 6NASA/Goddard Space Flight Center, USA
- 7AURA Astronomy, USA
Triton was observed by JWST/NIRSpec in December 2022, covering the 0.97-5.27 μm range at a spectral resolution R ~ 2700, as part of Cycle 1 GTO program #1272. In addition to the wealth of surface features due to N2, CH4, CO, CO2 ices and some of their isotopes, as well as organics in the 3.4-μm region, the spectra show the unambiguous signature of atmospheric CH4 (in absorption at 1.66, 2.3 and 3.3 μm) and CO (in fluorescent emission at 4.7 μm). These new data provide contemporary estimates of the abundances of these gases, for which past measurements have been scarce. CH4 appears enhanced by a factor ~4 compared to the Voyager epoch, and CO is estimated at the ~1000 ppm level within a factor of 3.
How to cite: Lellouch, E., L'opez-Puertas, M., Wong, I., Holler, B., Protopapa, S., Hines, D., Lunine, J., Milam, S., and Hammel, H.: CH4 and CO in Triton's atmosphere as seen by JWST, Europlanet Science Congress 2026, The Hague, The Netherlands, 7–11 Sep 2026, EPSC2026-403, https://doi.org/10.5194/epsc2026-403, 2026.
