# JWST molecular mapping and characterization of Enceladus' water plume feeding its torus

**Authors:** G. L. Villanueva, H. B. Hammel, S. N. Milam, V. Kofman, S. Faggi, C. R. Glein, R. Cartwright, L. Roth, K. P. Hand, L. Paganini, J. Spencer, J. Stansberry, B. Holler, N. Rowe-Gurney, S. Protopapa, G. Strazzulla, G. Liuzzi, G. Cruz-Mermy, M. El Moutamid, M. Hedman  
**arXiv:** [2305.18678](https://arxiv.org/abs/2305.18678)  
**Date:** 2023-05-30  
**Summary page:** https://www.summarizepaper.com/en/paper/2305.18678v1/

## Key points


## Summary

Enceladus, a moon of Saturn, has long been considered a prime target in the search for life in our solar system due to its active plume likely connected to a large liquid water subsurface ocean. Recently, using the sensitive NIRSpec instrument onboard JWST, scientists have searched for organic compounds and characterized the plume's composition and structure. The observations directly sample the fluorescence emissions of H2O and reveal an extraordinarily extensive plume (up to 10,000 km or 40 Enceladus radii) at cryogenic temperatures (25 K) embedded in a large bath of emission originating from Enceladus' torus. Interestingly, the observed outgassing rate (300 kg/s) is similar to that derived from close-up observations with Cassini 15 years ago. Moreover, the torus density is consistent with previous spatially unresolved measurements with Herschel 13 years ago, suggesting that the vigor of gas eruption from Enceladus has been relatively stable over decadal timescales. This level of activity is sufficient to maintain a derived column density of 4.5x1017 m-2 for the embedding equatorial torus and establishes Enceladus as the prime source of water across the Saturnian system. The team also conducted searches for several non-water gases such as CO2, CO, CH4, C2H6 and CH3OH but none were identified in the spectra. On the surface of the trailing hemisphere strong H2O ice features were observed including its crystalline form; however no CO2, CO nor NH3 ice signatures were recovered from these observations. As we prepare to send new spacecraft into outer solar system these observations demonstrate JWST's unique ability in providing critical support to exploring distant icy bodies and cryovolcanic plumes. With this new information on Enceladus' molecular mapping and characterization of its water plume feeding its torus scientists can continue to search for signs of life in our solar system.