Abstract
The first definite discoveries of extragalactic deuterium are reported. DCO+ has been detected in three and DCN has been measured in one star-forming region of the Large Magellanic Cloud (LMC). While the HCO+/DCO+ abundance ratios are found to be 19 +/- 3, 24 +/- 4, and 67 +/- 18 for N113, N44BC and N159HW, respectively, a HCN/DCN abundance ratio of 23 +/- 5 is obtained for N113. These results are consistent with a gas temperature of about 20 K and a D/H ratio of about 1.5 x 10(-5), consistent with that observed in the Galaxy. If the cloud temperature is closer to 30 K, then a D/H ratio is required to be up to an order of magnitude larger. Because this ratio provides a lower limit to the primordial D/H ratio, it indicates that the baryon mass density alone is unable to close the universe.
| Original language | English |
|---|---|
| Pages (from-to) | L33-L36 |
| Number of pages | 4 |
| Journal | Astronomy and Astrophysics |
| Volume | 312 |
| Publication status | Published - 1996 |
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Chin, Y. N., Henkel, C., Millar, TJ., Whiteoak, J. B., & Mauersberger, R. (1996). Molecular abundances in the Magellanic Clouds .2. Deuterated species in the LMC. Astronomy and Astrophysics, 312, L33-L36.