Detection of interstellar vibrationally excited HCN

Journal Article · Wed Jan 01 04:00:00 EST 1986 · Astrophys. J., Lett. Ed.; (United States)

DOI:https://doi.org/10.1086/184595· OSTI ID:6099680

Ziurys, L M; Turner, B E

Vibrationally excited HCN has been observed for the first time in the interstellar medium. The J = 3-2 rotational transitions of the l-doubled (0,1/sup 1d/,1c, 0) bending mode of HCN have been detected toward Orion-KL and IRC +10216. In Orion, the overall column density in the (0,1,0) mode, which exclusively samples the ''hot core,'' is 1.7-10/sup 16/ cm/sup -2/ and can be understood in terms of the ''doughnut'' model for Orion. The ground-state HCN column density implied by the excited-state observations is 2.3 x 10/sup 18/ cm/sup -2/ in the hot core, at least one order of magnitude greater than the column densities derived for HCN in its spike and plateau/doughnut components. Radiative excitation by 14 ..mu..m flux from IRc2 accounts for the (0,1,0) population provided the hot core is approx.6-7 x 10/sup 16/ cm distant from IRc2, in agreement with the ''cavity'' model for KL. Toward IRC +10216 we have detected J = 3-2 transitions of both (0,1/sup 1c/,/sup 1d/,0) and (0,2/sup 0/,0) excited states. The spectral profiles have been modeled to yield abundances and excitation conditions throughout the expanding envelope.

• Research Organization: Five College Radio Astronomy Observatory, University of Massachusetts, Amherst
• OSTI ID: 6099680
• Journal Information: Astrophys. J., Lett. Ed.; (United States), Journal Name: Astrophys. J., Lett. Ed.; (United States) Vol. 300:1; ISSN AJLEA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
CHEMICAL COMPOSITION
CHEMISTRY
COSMOCHEMISTRY
DATA
ELECTROMAGNETIC RADIATION
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXPERIMENTAL DATA
HYDRODYNAMIC MODEL
INFORMATION
INTERSTELLAR SPACE
MATHEMATICAL MODELS
NEBULAE
NUMERICAL DATA
PARTICLE MODELS
RADIAL VELOCITY
RADIATIONS
RADIOWAVE RADIATION
SPACE
SPECTRA
STATISTICAL MODELS
TEMPERATURE MEASUREMENT
THERMODYNAMIC MODEL
VELOCITY