Vibrationally Excited Lines of HC₃N Associated with the Molecular Disk around the G24.78+0.08 A1 Hypercompact H ii Region

Abstract We have analyzed Atacama Large Millimeter/submillimeter Array Band 6 data of the hypercompact H ii region G24.78+0.08 A1 (G24 HC ) and report detection vibrationally excited lines 3 N ( v 7 = 2, J 24 − 23). The spatial distribution kinematics a line 23, l 2 e are found to be similar CH CN 8 1), which indicates that emission is tracing disk around G24 previously identified by lines. derive 13 CN/HC CCN abundance ratios compare them in disks Herbig Ae T Tauri stars. (∼3.0–3.5) higher than other (∼0.03–0.11) more 1 order magnitude. suggest thermal desorption hot dense gas efficient destruction irradiated strong UV radiation occurring. Our results indicate can used as tracer massive protostars at stage, combination these nitrile species will provide information not only chemistry but also physical conditions structures.