Water fountains

These are interesting evolved objects with H2O maser emission spreading over large velocity ranges > 100 km/s. In all cases observed with radio interferometers, H2O maser emission traces highly collimated jets. They represent one of the first manifestations of collimated mass-loss in evolved stars and therefore, they are potentially key objects to understand the shaping process of planetary nebulae. Recently, I started a collaboration with Dr. Hiroshi Imai and his group to study these exciting sources.