Distance and kinematics of IRAS 19134+2131 revealed by H20 maser observations

摘要

Using the VLBA, we have observed H2 0 maser emission in the pre-planetary nebula,IRAS 19134+2131 (11913), in which the H2 0 maser spectrum has two groups of emission featuresseparated in radial velocity by ~100 km s~(-1).The morphology and 3-D kinematics indicate theexistence of a fast collimated flow with a dynamical age of only ~40 years. Such a "waterfountain" source is a signature of the recent operation of a stellar jet, that may be responsiblefor the final shape of the planetary nebula into which 11913 is expected to evolve. We have alsoestimated the distance to 11913 kpc) on the basis of an annual parallax and the kinematics ofIRAS 19134+2131 in our Galaxy. 11913 may be a component in the "thick disk" or the Galactic"warp", whose kinematics is different from that of the Galactic "thin" disk. These results arereported in Imai, Sahai & Morris (2007).