Observations of water masers associated with the proto-planetary nebula candidate IRAS 19296+2227

We present the first very long baseline interferometric observations of the 6(16)-5(23), 22 GHz H2O maser emission associated with a proto-planetary n ebula candidate. We obtained three epochs of observation of the water maser s associated with IRAS 19296+2227, using the Very Long Baseline Array, oper ated by the National Radio Astronomy Observatory. These observations show t hat the water masers are distributed over a 50 mas arclike structure coveri ng a limited velocity range of similar to 9 km s(-1). The masers most likel y reside in an asymptotic giant branch-like circumstellar shell, although w e cannot rule out the possibility that they lie in a shocked region. Over t he 40 days spanning the epochs of observation, we have measured an error-we ighted average proper motion of 6.16 +/- 1.32 km s(-1), indicating that the masers are not in a high-velocity outflow.