OBSERVATIONS OF SiO J = 3-2 AND J = 2-1 EMISSION IN LATE-TYPE STARS. II.

Abstract

Second observations of SiO v = 1, 2, J = 3-2 transitions, together with SiO v = 1, J = 2-1 transitions, have been performed toward 42 program late-type stars, using the 14 m radio telescope at Taeduk Radio Astronomy Observatory, from 1997 February to 1998 March. The v = 1, J = 3-2 maser was detected from 24 stars giving a detection rate of 57%, which is slightly higher than that of the first observations of 1995-1996. Four of these are new detections. For the v = 2, J = 3-2 maser, the line was detected from six stars including two new detections. The peak velocities and the velocity patterns of the v = 1, J = 3-2 masers are different from those of the v = 1, J = 2-1 indicating a difference in the traced regions. The average total photon flux of the v = 1, J = 3-2 maser is estimated to be 10{sup 42.7}, that of the v = 2, J = 3-2 maser 10{sup 42.2}, and that of the v = 1, J = 2-1 maser 10{sup 43.2} photons s{sup -1}. In addition, we confirm that the v = 2, J = 4-3 masermore » is stronger than the v = 1, J = 4-3.« less