Poster abstract details

A "Water fountain" is a transitional object between an AGB star and a PNe. The VLBA observations of 22.2GHz water maser emission reveal a "double-helix" outflow pattern from one of the water fountains, IRAS 18286-0959. The pattern is reasonably fit by a model consisting of two precessing jets. We propose that the appearance of two jets observed are the result of a single driving source with a significant proper motion. We also exam the infrared properties of water fountains and found that they might have their own IR color characteristics which are not suggested in previous color classifications (e.g. van der Veen & Habing 1988). The IR color of water fountains could serve as a new criteria for searching this type of rare objects.