1996A&AS..115..117C

Simultaneous observations of the ²⁸SiO v=0, 1, 2, and 3, J=1-0 and ²⁹SiO v=0 and 1, J=1-0 transitions for 102 late-type stars were made with a sensitivity of about 2Jy at the 3σ level using the 45 m telescope of Nobeyama Radio Observatory (NRO). SiO maser emission was detected in 83 stars; seven of them being new detections. The v=3 maser was detected in 12 stars with eight new detections. Most of the v=3 masers occur at the same radial velocity of the strongest spikes of the v=1 and 2 masers. We also newly found the ²⁹SiO v=0 maser in six stars. The ²⁹SiO v=0 line is stronger and narrower than the ²⁸SiO v=0 line, indicating that the ²⁹SiO line is masing. In most cases, the ²⁹SiO line shows a single narrow profile (FWHM=1 to 3km/s), with peak radial velocities coincident with the stellar velocity derived from OH maser and/or SiO/CO thermal lines within 1km/s. Therefore, this maser line provides excellent means to measure the stellar velocities of late-type stars. The ²⁸SiO v=0, J=1-0 line was detected in eleven stars, with three new detections.