Precise observations of the {sup 12}C/{sup 13}C ratios of HC{sub 3}N in the low-mass star-forming region L1527
- Department of Chemistry, Faculty of Science Division I, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan)
- Department of Physics, General Studies, College of Engineering, Nihon University, 1 Nakagawara, Tokusada, Tamuramachi, Koriyama, Fukushima 963-8642 (Japan)
- The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)
- Department of Physics and Research Center for the Early Universe, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan)
- Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554 (Japan)
Using the Green Bank 100 m telescope and the Nobeyama 45 m telescope, we have observed the rotational emission lines of the three {sup 13}C isotopic species of HC{sub 3}N in the 3 and 7 mm bands toward the low-mass star-forming region L1527 in order to explore their anomalous {sup 12}C/{sup 13}C ratios. The column densities of the {sup 13}C isotopic species are derived from the intensities of the J = 5–4 lines observed at high signal-to-noise ratios. The abundance ratios are determined to be 1.00:1.01 ± 0.02:1.35 ± 0.03:86.4 ± 1.6 for [H{sup 13}CCCN]:[HC{sup 13}CCN]:[HCC{sup 13}CN]:[HCCCN], where the errors represent one standard deviation. The ratios are very similar to those reported for the starless cloud Taurus Molecular Cloud-1 Cyanopolyyne Peak (TMC-1 CP). These ratios cannot be explained by thermal equilibrium, but likely reflect the production pathways of this molecule. We have shown the equality of the abundances of H{sup 13}CCCN and HC{sup 13}CCN at a high-confidence level, which supports the production pathways of HC{sub 3}N via C{sub 2}H{sub 2} and C{sub 2}H{sub 2}{sup +}. The average {sup 12}C/{sup 13}C ratio for HC{sub 3}N is 77 ± 4, which may be only slightly higher than the elemental {sup 12}C/{sup 13}C ratio. Dilution of the {sup 13}C isotope in HC{sub 3}N is not as significant as that in CCH or c-C{sub 3}H{sub 2}. We have also simultaneously observed the DCCCN and HCCC{sup 15}N lines and derived the isotope ratios [DCCCN]/[HCCCN] = 0.0370 ± 0.0007 and [HCCCN]/[HCCC{sup 15}N] = 338 ± 12.
- OSTI ID:
- 22869625
- Journal Information:
- Astrophysical Journal, Vol. 833, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Implication of formation mechanisms of HC{sub 5}N in TMC-1 as studied by {sup 13}C isotopic fractionation
{sup 13}C Isotopic Fractionation of HC{sub 3}N in Two Starless Cores: L1521B and L134N (L183)