Water masers in the Saturnian system
Gurvits, L. I.; Pogrebenko, S. V.; Mujunen, A.; Ritakari, J.; Avruch, I. M.; Elitzur, M.; Wagner, J.; Cosmovici, C. B.; Montebugnoli, S.; Salerno, E.; Pluchino, S.; Maccaferri, G.; Molera, G.; Uunila, M.
Netherlands, United States, Italy, Finland
Abstract
Context: The presence of water has long been seen as a key condition for life in planetary environments. The Cassini spacecraft discovered water vapour in the Saturnian system by detecting absorption of UV emission from a background star. Investigating other possible manifestations of water is essential, one of which, provided physical conditions are suitable, is maser emission.
Aims: We report detection of water maser emission at 22 GHz associated with several Kronian satellites using Earth-based radio telescopes.
Methods: We searched for water maser emission in the Saturnian system in an observing campaign using the Metsähovi and Medicina radio telescopes. Spectral data were Doppler-corrected over orbital phase for the Saturnian satellites, yielding detections of water maser emission associated with the moons Hyperion, Titan, Enceladus, and Atlas.
Results: The detection of Saturnian water molecules by remote astronomical observation can be combined with in situ spacecraft measurements to harmonise the physical model of the Saturnian system.