CO and Atomic Line Emission from the Young Stellar Object V1331 Cygni

Abstract

The infrared spectrum of the young disk star V1331 Cygni shows rare atomic emission lines from several species including C i, O i, Na i, Mg i, Al i, Si i, Ca i, Fe i, and probably S i. The presence of H i emission but the absence of N i recombination lines indicates excitation by a comparatively cool source unable to ionize nitrogen. Measurements of both the fundamental and first overtone emission of carbon monoxide indicate a hot (T ≈ 3000 K), optically thick (optical depth ≈100 in the strongest transitions of the fundamental) for the molecular gas.