Description
This paper presents new results of a water maser survey of late-type stellar objects at 22.235GHz with the Kashima 34-m radio telescope. We have detected 179 out of 643 observed sources, including 32 new detections. The sources were selected in terms of the IRAS flux density and colors of late-type stars, involving optically observable Mira/semi-regular variables, IRC objects, OH/IR sources and proto-planetary nebulae. We found the highest H_2_O detection rate for the type of stars with a thin dust envelope (Mira/semi-regular variables) among other types of sources. This is attributed to the smaller distances to such stars in the sample. The velocity spread of the H_2_O maser profile has an increasing tendency with the IRAS color, though it becomes more difficult to access this color dependence beyond an edge of the transition of the (oxygen-rich) Asymptotic Giant Branch stars to protoplanetary nebulae in the two-color diagram.
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