Unresolved velocity structure in diffuse interstellar clouds

Details Unresolved velocity structure in diffuse interstellar clouds Unresolved velocity structure in diffuse interstellar clouds

Aug 1988

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1988apj...331..986b&link_type=abstract

Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 331, Aug. 15, 1988, p. 986-998.

Astronomy and Astrophysics

Astrophysics

56

Interstellar Matter, Line Spectra, Molecular Clouds, Stellar Spectra, Absorption Spectra, Abundance, Carbon Compounds, High Temperature, Light Curve, Ultraviolet Radiation, Velocity Distribution

Scientific paper

Recent high-resolution observations of interstellar absorption lines of CH and CN toward Zeta Oph obtained by Crane et al. (1986), and Palazzi et al. (1988), exhibit line widths that suggest thermal line broadening at high temperature, T about 1200 K. Observations of CO line emission at 2.6 mm toward Zeta Oph (Langer et al.,1987) indicate that the molecular gas resides in four distinct velocity components that span less than 3 km/s in Doppler velocity. Simulated CH and CN absorption line profiles are compared for high-temperature (T = 1200 K) thermal broadening and for a combination of low-temperature (T = 50 K) thermal plus turbulent broadening. It is shown that the two broadening models reproduce existing observations comparably well and are virtually indistinguishable at a lambda/Delta-lambda ratio of about 100,000. The observed differences in the CH and CN line widths may reflect slightly different distributions of those molecules along the line of sight. The simulations use very recent, improved laboratory spectroscopic data on CH (Bernath). Some related consequences of such unresolved velocity structure on the ultraviolet absorption lines of CO are examined. Indirect diagnostics of temperature in the Zeta Oph cloud favor low-temperature thermal plus turbulent broadening, and the implied rate of dissipation of turbulence is in harmony with estimates of the global input of mechanical energy into to interstellar medium.

Affiliated with

Also associated with

No associations

Rating

Unresolved velocity structure in diffuse interstellar clouds does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Unresolved velocity structure in diffuse interstellar clouds, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Unresolved velocity structure in diffuse interstellar clouds will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1693679