A deep envelope composition for TX Piscium

Observations of the carbon star TX Psc (for which the angular diameter and effective temperature have been independently established) are reported at high resolution in the 4000 cm −1 spectral region and at moderate resolution from 2500 to 8000 cm −1 . Model atmospheres of carbon stars with normal solar oxygen abundance and deep envelope composition are presented that include HCN and C 2 H 2 (polyatomics) line opacity using the opacity sampling technique