Deuterium in the Sagittarius B2 and Sagittarius A galactic center regions

Details Deuterium in the Sagittarius B2 and Sagittarius A galactic center regions Deuterium in the Sagittarius B2 and Sagittarius A galactic center regions

Jul 1999

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1999a%26a...347..957j&link_type=abstract

Astronomy and Astrophysics, v.347, p.957-966 (1999)

Astronomy and Astrophysics

Astrophysics

12

Ism: Abundances, Ism: Molecules, Galaxy: Center, Radio Lines: Ism

Scientific paper

We report IRAM 30-m observations of DCN and DCO(+) \ towards the galactic center molecular clouds Sgr B2 and Sgr A. We compare our results with simultaneous measurements of H(13) CN and HC(18) O(+) in order to derive estimates of the [DCN]/[HCN] and [DCO(+) ]/[\HCOP] abundance ratios. We mapped Sgr B2 in DCN(2-1) and DCN(3-2) and we compared HC(15) N with DCN for one position of our maps. The uncertainties in such measurements turn out to be large, due to optical depth effects, in the case of \HTHCN, and, in the case of Sgr B2, due to the strong foreground absorption in \HTHCN, HC(15) N and \HCEIOP. Taking these effects into account, we conclude that [DCN]/[HCN] towards the molecular ridge in Sgr B2 is 1.3 10(-4) (uncertain by a factor 2) and towards the Sgr A molecular cloud is < 6 10(-4) . Towards Sgr B2, we also estimate [DCO(+) ]/[\HCOP] to be 2 10(-4) again with a factor of 2 uncertainty. We have carried out model calculations to estimate the amount of deuterium enhancement in these species in these clouds. We find, for temperatures between 40 and 120 K, that one expects D to be enhanced in DCN in the galactic center by a factor between 12 and 140 over the actual ratio of [D/H]. The corresponding enhancement for DCO(+) \ would be between 23 and 460. Based on these results, we conclude that the ratio of [D/H] in the Sgr B2 cloud is 5 10(-6) with a factor of 10 uncertainty. This result, while it has large uncertainty, suggests that deuterium is roughly one order of magnitude less abundant in the galactic center than in the solar neighbourhood. We briefly discuss possible consequences of this for the stellar initial mass function in the galactic center.

Affiliated with

Also associated with

No associations

Rating

Deuterium in the Sagittarius B2 and Sagittarius A galactic center regions 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 Deuterium in the Sagittarius B2 and Sagittarius A galactic center regions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Deuterium in the Sagittarius B2 and Sagittarius A galactic center regions will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1617340