title: Abundance Anomaly of 13C Isotopic Species of c-C3H2

authors: K. Yoshida, N. Sakai, T. Tokudome, A. Lopez-Seplcre, Y. Watanabe (The Univ. of Tokyo), Shuro Takano (NRO/SOKENDAI), B. Lefloch, C. Ceccarelli (Univ. Grenoble Alpes/CNRS), R. Bachiller (OAN, IGN), E. Caux, C. Vastel (Univ. Toulouse) and S. Yamamoto (The Univ. of Tokyo)

abstract: It has been reported that the 12C/13C ratios of several carbon-chain molecules in cold clouds are significantly higher than the interstellar elemental 12C/13C ratio of 60-70. In addition, two or more 13C species of a single molecular species have different abundances.  
We recently found the similar anomaly for c-C3H2 toward low-mass star-forming region L1527. Many lines of c-C3H2 and its 13C species detected in the spectral line surveys with the NRO 45 m and the IRAM 30 m telescopes enable us to derive the 12C/13C ratios for the two 13C species accurately. We found a significant dilution of the 13C species, and a significant difference in abundance between two isotopic species of c-C3H2. These results further confirm that the 13C anomaly is an important phenomenon in astrochemistry.