Evolution of the Outflow Traced by Water Masers in the Evolved Star IRAS 18043—2116

We present the spectral and spatial evolution of H 2 O masers associated with IRAS 18043–2116, a well-known water fountain hosting a high-velocity collimated jet, which has been found in the observations with the 45 m telescope of Nobeyama Radio Observatory and the Australia Telescope Compact Array. We found new highest velocity components of the H 2 O masers, with which the resulting velocity spread of ≃ 540 km s −1 breaks the speed record of fast jets/outflows in this type of sources.