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A survey of N2H(+) in dense clouds - Implications for interstellar nitrogen and ion-molecule chemistry

1992; IOP Publishing; Volume: 387; Linguagem: Inglês

10.1086/171094

1538-4357

M. Womack, L. M. Ziurys, S. Wyckoff,

Atmospheric Ozone and Climate

view Abstract Citations (65) References (65) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Survey of N 2H + in Dense Clouds: Implications for Interstellar Nitrogen and Ion-Molecule Chemistry Womack, M. ; Ziurys, L. M. ; Wyckoff, S. Abstract Attention is given to spectra of the N2(H(+) J = 1 - 0, J = 3 - 2 and (N-15)NH(+) and N(N-15)H(+) J = 1 - 0 rotational transitions obtained toward a sample of star-forming and cold dark clouds in the Galaxy. Toward the star-forming regions, line profiles are relatively narrow (typically 1-5 km/s) and show no evidence of line wings, in contrast to the spectra of HCO(+). It is inferred from the apparent absence of N2H(+) in hot, shocked gas that this ion may be a selective tracer of extended, quiescent material. Column densities of N2H(+) were found to be about 5 x 10 exp 12/sq cm toward cold clouds and about 10 exp 14/sq cm toward warm clouds. These values correspond to fractional abundances, relative to H2, of about 4 x 10 exp -10 toward both the warm and cold clouds. It is concluded that the abundance and distribution of N2H(+) is well explained by the ion-molecule chemistry, provided it has reached the steady state, as is found for interstellar NH3. The N2H(+) results are advanced as further evidence that interstellar nitrogen chemistry is anomalous. Publication: The Astrophysical Journal Pub Date: March 1992 DOI: 10.1086/171094 Bibcode: 1992ApJ...387..417W Keywords: Azo Compounds; Interstellar Chemistry; Interstellar Matter; Molecular Clouds; Dark Matter; Electron Transitions; Emission Spectra; Formyl Ions; Molecular Rotation; Spectral Line Width; Astrophysics; ISM: ABUNDANCES; ISM: MOLECULES; MOLECULAR PROCESSES full text sources ADS | data products SIMBAD (17)