Detection of interstellar rotationally excited CH

Journal Article · Wed May 01 00:00:00 EDT 1985 · Astrophys. J., Lett. Ed.; (United States)

DOI:https://doi.org/10.1086/184466· OSTI ID:5659840

Ziurys, L M; Turner, B E

Rotationally excited CH has been detected for the first time in the ISM. The first excited level (F/sub 1/, N = 1, J = 3/2) has been observed via its ..lambda..-doubling transitions at 700 MHz toward W51: the lowest frequency molecular lines detected to date. The two main hyperfine components are seen in absorption. The spectra qualitatively resemble the line profiles of the ground state at the same position, suggesting that both transitions originate in the same gas. The column density derived for the excited state is at least NL> or =1.2--1.4 x 10/sup 14/ cm/sup -2/, comparable to that of the ground state in W51, but could be as high as 9.8 x 10/sup 17/ cm/sup -2/. The large excited-state population cannot apparently be explained by far-infrared radiative excitation from dust; collisions with gas densities n(H/sub 2/)> or =10/sup 6/ cm/sup -3/ are probably the dominant source of excitation. CH is therefore present with considerable abundance at high densities in W51, contrary to predictions of chemical models.

• Research Organization: Department of Chemistry and Radio Astronomy Laboratory, University of California, Berkeley
• OSTI ID: 5659840
• Journal Information: Astrophys. J., Lett. Ed.; (United States), Vol. 292:1
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
HYDROCARBONS
ROTATIONAL STATES
INTERSTELLAR SPACE
ABUNDANCE
COSMIC RADIO SOURCES
DIAGRAMS
ENERGY LEVELS
EXCITATION
EXPERIMENTAL DATA
HYPERFINE STRUCTURE
INTERSTELLAR GRAINS
MOLECULES
TABLES
DATA
ENERGY-LEVEL TRANSITIONS
EXCITED STATES
INFORMATION
NUMERICAL DATA
ORGANIC COMPOUNDS
PARTICLES
SPACE
640105* - Astrophysics & Cosmology- Galaxies