Disklike structure in the semiregular pulsating star x herculis

Abstract

This paper reports the results of a Berkeley-Illinois-Maryland (BIMA) array interferometric observation of a semiregular pulsating star with an unusual narrow molecular line profile, X Her, in the CO J = 1-0 line. In the CO spectrum, a double-component profile (including narrow and broad components) is seen, as reported by previous observations. The narrow component consists of two spiky peaks. The spatial structure of the board component shows bipolar shape, and that of the narrow component shows an elliptical/spherical shape. The two peaks in the narrow component show a systematic difference in the integrated intensity map. The kinematical and geometrical properties of the narrow component are reminiscent of a Keplerian rotating disk with a central mass of 0.9 M ⊙, although an interpretation as an expansion disk seems to be more natural. A secondary bipolar flow instead of the disk also cannot be fully excluded as an interpretation of the narrow line. © 2005. The American Astronomical Society. All rights reserved.