Millimeter observations of ^12^CO and ^ 13^CO in the diffuse region around ζ Ophiuchi.

Astronomy and Astrophysics – Astrophysics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

14

Radio Lines: Ism, Ism: Abundances, Ism: Molecules, Ism: Clouds, Ism: Individual Objects: {Zeta} Oph

Scientific paper

Using the 15-m SEST submillimeter telescope, we have observed ^12^CO and ^13^CO in the diffuse molecular cloud lying close to ζ Oph, and searched for C^18^O, CS, CN and HCO^+^ at 2 particular positions. The ^12^CO(1-0) measurements show lines of the order of a few Kelvins in regions where the ^13^CO data seem to indicate diffuse material. We measure ^12^CO(1-0)/^13^CO(1-0) ratios of the order of 30 toward the positions of peak CO emission and lower limits of this ratio up to 65 in more diffuse regions. We compare these data with the predictions of a chemical model which solves consistently the thermal and chemical equilibrium of an interstellar cloud and computes the submillimeter and millimeter emergent line intensities of various atomic and molecular transitions. For the positions of peak CO emission, the model and observations agree satisfactorily for an isobaric cloud of pressure p=7.5x10^4^Kcm^-3^ or an isochoric cloud of density n(H_2_)=2500cm^-3^ permeated by an UV radiation field enhanced by a factor of 5 compared to the standard interstellar radiation field (ISRF) of Mathis et al. (???). The excitation properties of CO are consistent with a visual magnitude of the order of 1.2. The upper limit found for CS is also reproduced if the gas phase sulfur abundance is lower than the recent HST determinations.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Millimeter observations of ^12^CO and ^ 13^CO in the diffuse region around ζ Ophiuchi. 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 Millimeter observations of ^12^CO and ^ 13^CO in the diffuse region around ζ Ophiuchi., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Millimeter observations of ^12^CO and ^ 13^CO in the diffuse region around ζ Ophiuchi. will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-967001

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.