13C Isotopic Fractionation of HC3N in Star-Forming Regions -Low-Mass Star Forming Region L1527 and High-Mass Star Forming Region G28.28-0.36-

TL;DR

This study investigates the 13C isotopic fractionation of HC3N in low- and high-mass star-forming regions, revealing similar fractionation patterns that suggest a common formation pathway via neutral-neutral reactions.

Contribution

It provides the first detailed comparison of 13C isotopic ratios of HC3N in different star-forming environments, highlighting a common formation mechanism.

Findings

Similar 13C isotopic fractionation patterns in both regions

H13CCCN and HC13CCN are similarly abundant, HCC13CN is more abundant

Formation likely via neutral-neutral reactions between C2H2 and CN

Abstract

We observed the J=9-8 and 10-9 rotational lines of three13C isotopologues of HC3N in L1527 and G28.28-0.36 with the 45-m radio telescope of the Nobeyama Radio Observatory in order to constrain the main formation mechanisms of HC3N in each source. The abundance ratios of the three 13C isotopologues of HC3N are found to be 0.9 (0.2) : 1.00 : 1.29 (0.19) (1sigma) and 1.0 (0.2) : 1.00 : 1.47 (0.17) (1sigma) for [H13CCCN]: [HC13CCN]: [HCC13CN] in L1527 and G28.28-0.36, respectively. We recognize a similar 13C isotopic fractionation pattern that the abundances of H13CCCN and HC13CCN are comparable, and HCC13CN is more abundant than the others. Based on the results, we discuss the main formation pathway of HC3N. The 13C isotopic fractionation pattern derived from our observations can be explained by the neutral-neutral reaction between C2H2 and CN in both the low-mass (L1527) and high-mass (28.28-0.36) star forming regions.