Astrochemistry

Spatial Distribution of C4H and c-C3H2 in Cold Molecular Cores

By Keith Cowing

Status Report

astro-ph.GA

July 3, 2024

Filed under astro-ph.GA, astrochemistry, buiochemistry, cold molecular core, Interstellar, interstellar medium, organic chemistry, Spectroscopy

Spatial Distribution of C4H and c-C3H2 in Cold Molecular Cores — The velocity integrated maps and spatial averaged spectra of C4H 9–8, c-C3H2 2–1 and H13CO+ 1–0. The source names are presented in the maps and spectra. The gray scale color at the right is in units of K km s−1 . (a): The velocity integrated intensity maps for C4H 9–8 (magenta contours), c-C3H2 2–1 (blue contours) and H13CO+ 1–0 (green contours) of G001.38+20. (b): The same as Figure 1(a) but for G001.84+16. (c): Spectra of C4H at 85672.5793 MHz, c-C3H2 at 85338.8940 MHz and H13CO+ at 86754.2884 MHz in the yellow box of G001.38+20. (d): The same as Figure 1(c) but for G001.84+16. The detailed mapping information of all sources for C4H 9–8, c-C3H2 2–1 and H13CO+ 1–0 are listed in Table 4. — astro-ph.GA

C₄H and c-C₃H₂, as unsaturated hydrocarbon molecules, are important for forming large organic molecules in the interstellar medium. We present mapping observations of C₄H (N=9−8) lines, c-c-C₃H₂ (JKa,Kb=21,2-10,1) %at 85338.894 MHz and H¹³CO⁺ (J=1−0) %at 86754.2884 MHz toward 19 nearby cold molecular cores in the Milky Way with the IRAM 30m telescope. C₄H 9–8 was detected in 13 sources, while c-C₃H₂ was detected in 18 sources.

The widely existing C4H and c-C₃H₂ molecules in cold cores provide material to form large organic molecules. Different spatial distributions between C4H 9–8 and c-C₃H₂ 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 C₄H to c-C₃H₂ ranged from 0.34 ± 0.09 in G032.93+02 to 4.65 ± 0.50 in G008.67+22.

A weak correlation between C₄H/H¹³CO+ and c-C₃H₂/H¹³CO+ abundance ratios was found, with a correlation coefficient of 0.46, which indicates that there is no tight astrochemical connection between C₄H and c-C₃H₂ molecules.

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

Comments: 17 pages, 2 figures
Subjects: Astrophysics of Galaxies (astro-ph.GA)
Cite as: arXiv:2406.19740 [astro-ph.GA] (or arXiv:2406.19740v1 [astro-ph.GA] for this version)
Related DOI:
https://doi.org/10.3847/1538-4357/ad47a3
Focus to learn more
Submission history
From: Yijia Liu
[v1] Fri, 28 Jun 2024 08:28:04 UTC (648 KB)
https://arxiv.org/abs/2406.19740
Astrobiology, Astrochemistry,

Keith Cowing

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻

Follow on Twitter