Presentation #147.05 in the session Laboratory Astrophysics (LAD) Division Meeting: iPoster Session.
We report observations of the C-rich AGB stars IRC +10216 and CIT 6 and the O-rich IK Tau obtained with the Arizona Radio Observatory Submillimeter Telescope. The observations focused on rotational emission lines of SiO, CO, CS, and SiS and other features over the frequency range 213-360 GHz. To explore time-variations in the strong molecular lines, observations were made at four epochs (Nov. 2020, Dec. 2020, April 2021, May 2021). Preliminary analysis of the SiO 5-4 line finds a 20% variation in the intensity over this epoch range. Non-LTE models of the diatomic spectra will be presented. Further, we carried out a partial survey for CIT 6 at frequencies higher than the upper limit of 268 GHz from previous work.