An Etymological Dictionary of Astronomy and Astrophysics

A system for the classification of → S-type stars. The system involves the designations of a C/O index and a temperature type. Moreover, when possible, it uses intensity estimates for → ZrO bands, the → TiO bands, the → Na I D-lines, the YO bands, and the Li I 6708 line.

See also: Philip C. Keenan & Patricia C. Boeshaar, 1980, ApJS, 43, 379; → classification.