Knacke R F, Kim Y H, Irvine W M
State University of New York at Stony Brook, USA.
Astrophys J. 1989 Oct 1;345(1):265-7. doi: 10.1086/167902.
We report a search for the acetylene (C2H2) nu 3 infrared vibration-rotation absorption near 3 micrometers toward the Becklin-Neugebauer source in the Orion molecular cloud. The relative abundance of C2H2/CO in the quiescent gas (9 km s-1 component) is less than 3 x 10(-3) (5 sigma).