Spatial distribution of C4H and c-C3H2 in cold molecular cores

Yijia Liu; Junzhi Wang; Shu Liu; Ningyu Tang; Yan Gong; Yuqiang Li; Juan LI; Rui Luo; Yani Xu

doi:10.3847/1538-4357/ad47a3

paper

Spatial distribution of C4H and c-C3H2 in cold molecular cores

arXiv:2406.19740 · doi:10.3847/1538-4357/ad47a3

Abstract

C $_{4}$ H and $c$ -C $_{3}$ H $_{2}$ , as unsaturated hydrocarbon molecules, are important for forming large organic molecules in the interstellar medium. We present mapping observations of C $_{4}$ H ( $N$ =9 $- 8$ ) lines, $c$ -C $_{3}$ H $_{2}$ ( $J_{K a, K b}$ =2 $_{1, 2}$ -1 $_{0, 1}$ ) %at 85338.894 MHz and H $^{13}$ CO $^{+}$ ( $J$ =1 $- 0$ ) %at 86754.2884 MHz toward 19 nearby cold molecular cores in the Milky Way with the IRAM 30m telescope. C $_{4}$ H 9--8 was detected in 13 sources, while $c$ -C $_{3}$ H $_{2}$ was detected in 18 sources. The widely existing C $_{4}$ H and $c$ -C $_{3}$ H $_{2}$ molecules in cold cores provide material to form large organic molecules. Different spatial distributions between C $_{4}$ H 9--8 and $c$ -C $_{3}$ H $_{2}$ 2--1 were found. The relative abundances of these three molecules were obtained under the assumption of local thermodynamic equilibrium conditions with a fixed excitation temperature. The abundance ratio of C $_{4}$ H to $c$ -C $_{3}$ H $_{2}$ ranged from 0.34 $\pm$ 0.09 in G032.93+02 to 4.65 $\pm$ 0.50 in G008.67+22. A weak correlation between C $_{4}$ H/H $^{13}$ CO $^{+}$ and $c$ -C $_{3}$ H $_{2}$ /H $^{13}$ CO $^{+}$ abundance ratios was found, with a correlation coefficient of 0.46, which indicates that there is no tight astrochemical connection between C $_{4}$ H and $c$ -C $_{3}$ H $_{2}$ molecules.

arXiv comment17 pages, 2 figures

References in corpus (14)

Cited by in corpus (1)

The evolution of C4H and c-C3H2 in molecular cores