DETECTION OF THE (SIO)-SI-29 UPSILON=1, J=1-0 MASER FROM TX-CAMELOPARDALIS

The maser emission from the v = 1, J = 1-0 transition of (SiO)-Si-29 h as been detected for the first time toward the Mira variable star TX C am among 54 surveyed late-type stars. The line was fairly narrower tha n the (SiO)-Si-29 v = 0, J = 1-0 transition, and slightly redshifted c ompared to the v = 0 line. In addition, the (SiO)-Si-28 v = 2, J = 2-1 transition has also been newly detected in this star. Based on the li ne intensity, the pumping mechanism for the (SiO)-Si-29 v = 1, J = 1-0 maser is discussed. The simple large velocity-gradient model and the line overlap of H2O can not be adopted for this maser.