CARBON ISOTOPE FRACTIONATION AND DEPLETION IN TMC1
- National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475 (United States)
{sup 12}C/{sup 13}C isotopologue abundance anomalies have long been predicted for gas-phase chemistry in molecules other than CO and have recently been observed in the Taurus molecular cloud (TMC) in several species hosting more than one carbon atom, i.e., CCH, CCS, CCCS, and HC{sub 3}N. Here we work to ascertain whether these isotopologic anomalies actually result from the predicted depletion of the {sup 13}C{sup +} ion in an oxygen-rich optically shielded dense gas, or from some other more particular mechanism or mechanisms. We observed {lambda}3mm emission from carbon-, sulfur-, and nitrogen-bearing isotopologues of HNC, CS, and H{sub 2}CS at three positions in Taurus (TMC1, L1527, and the NH{sub 3} peak) using the ARO 12 m telescope. We saw no evidence of {sup 12}C/{sup 13}C anomalies in our observations. Although the pool of C{sup +} is likely to be depleted in {sup 13}C, {sup 13}C is not depleted in the general pool of carbon outside CO, which probably exists mostly in the form of C{sup 0}. The observed isotopologic abundance anomalies are peculiar to those species in which they are found.
- OSTI ID:
- 22016295
- Journal Information:
- Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 747; ISSN ASJOAB; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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