Abstract:
Spectrograms in the 6040-7300 A wavelength region of the S star Pi Gruis reveal the presence of new molecular features attributable to CeO. Measures of band heads compared reasonably well with the laboratory spectrum. The proposed identifications are supported by the recent high resolution spectral studies of CeO in R Gem and R And. A discussion based on the identified molecular features is included on the classification of Pi Gruis as a pure S-type star.