On the excitation of interstellar ammonia in the Kleinmann-Low nebula

Details On the excitation of interstellar ammonia in the Kleinmann-Low nebula On the excitation of interstellar ammonia in the Kleinmann-Low nebula

Oct 1978

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1978apj...225..116s&link_type=abstract

Astrophysical Journal, Part 1, vol. 225, Oct. 1, 1978, p. 116-129.

Astronomy and Astrophysics

Astrophysics

56

Ammonia, Interstellar Gas, Molecular Excitation, Nebulae, Abundance, Astronomical Models, Collision Rates, Energy Levels, Hyperfine Structure, Iterative Solution, Line Shape, Thermodynamic Equilibrium

Scientific paper

Investigations of the region in which NH3 lines are formed in the direction of the Kleinmann-Low nebula are reported. A non-LTE model, including the transfer of both the line radiation and the dust-generated continuum radiation, was constructed to study the excitation of the lowest 31 levels of NH3. Agreement between the model and the observations is excellent. The model implies relatively high densities (of the order of 1 million H2 molecules/cu cm) and temperatures (about 70 K) for the line formation region. These results further imply that the lines come from a small (about 16 arcsec) core with an optical depth of approximately 0.02 in the dust continuum at 250 microns. The problem of the NH3 line shapes is also studied, and a relative NH3 abundance of approximately 5 ten-millionths is derived, which is a factor of about 1000 higher than ion-molecule predictions. This abundance is, however, consistent with the abundance of NH3 ice on grains seen toward the BN object if the interpretation of the 3-micron feature as H2O and NH3 ices is correct. It is suggested that the extreme NH3 clumping implied by the 16-arcsec core may be due to evaporation of NH3 from grains in the Kleinmann-Low nebula.

Affiliated with

Also associated with

No associations

Rating

On the excitation of interstellar ammonia in the Kleinmann-Low nebula 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 On the excitation of interstellar ammonia in the Kleinmann-Low nebula, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and On the excitation of interstellar ammonia in the Kleinmann-Low nebula will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1689835