1995A&A...303L..25V

Thorne-Zytkow objects (TZO) are likely to have high mass loss rates, such that their optical photospheres are obscured by a dusty envelope. Indentification of massive TZO through abundance anomalies associated with the irp process in the core is more likely to be possible by observing molecular transitions in the 4-8 µm region and at mm wavelengths than in the optical. A promising molecule is SiO, with anomalously high abundances predicted for ²⁹SiO and ³⁰SiO. An upper limit for ³⁰SiO is reported for the unusually bright galactic center SiO maser OH359.762+0.120.