Recent infrared spectroscopy from the James Webb Space Telescope (JWST) has spurred analyses of common volcanic gases such as carbon dioxide (CO2), sulfur dioxide (SO2), alongside alkali metals sodium (Na I) and potassium (K I) surrounding the hot Saturn WASP-39 b. We report more than an order-of-magnitude of variability in the density of neutral Na, K, and SO2 between ground-based measurements and JWST, at distinct epochs, hinting at exogenic physical processes similar to those sourcing Io's extended atmosphere and torus. Tidally-heated volcanic satellite simulations sputtering gas into a cloud or toroid orbiting the planet, are able to reproduce the probed line-of-sight column density variations. The estimated SO2 flux is consistent with tidal gravitation predictions, with a Na/SO2 ratio far smaller than Io's. Although stable satellite orbits at this system are known to be < 15.3 hours, several high-resolution alkali Doppler shift observations are required to constrain a putative orbit. Due to the Roche limit interior to the planetary photosphere at ~ 8 hours, atmosphere-exosphere interactions are expected to be especially important at this system.
@article{arxiv.2509.08349,
title = {Volcanic Satellites Tidally Venting Na, K, SO2 in Optical & Infrared Light},
author = {Apurva V. Oza and Andrea Gebek and Moritz Meyer zu Westram and Armen Tokadjian and Anthony L. Piro and Renyu Hu and Athira Unni and Raghav Chari and Aaron Bello-Arufe and Carl A. Schmidt and Amy J. Louca and Yamila Miguel and Raissa Estrela and Jeehyun Yang and Mario Damiano and Yasuhiro Hasegawa and Luis Welbanks and Diana Powell and Rishabh Garg and Pulkit Gupta and Yuk L. Yung and Rosaly M. C. Lopes},
journal= {arXiv preprint arXiv:2509.08349},
year = {2025}
}
Comments
10 pages, 5 figures, accepted for publication in the Monthly Notices of the Royal Astronomical Society