Survey Observations to Study Chemical Evolution from High-mass Starless Cores to High-mass Protostellar Objects I: HC3N and HC5N

Abstract

We carried out survey observations of HC${}_3$N and HC${}_5$N in the 42$-$45 GHz band toward 17 high-mass starless cores (HMSCs) and 35 high-mass protostellar objects (HMPOs) with the Nobeyama 45 m radio telescope. We have detected HC${}_3$N from 15 HMSCs and 28 HMPOs, and HC${}_5$N from 5 HMSCs and 14 HMPOs, respectively. The average values of the column density of HC${}_3$N are found to be ($5.7\pm 0.7$)$\times 10^{12}$ and ($1.03\pm 0.12$)$\times 10^{13}$ cm${}^{-2}$ in HMSCs and HMPOs, respectively. The average values of the fractional abundance of HC${}_3$N are derived to be ($6.6\pm 0.8$)$\times 10^{-11}$ and ($3.6\pm 0.5$)$\times 10^{-11}$ in HMSCs and HMPOs, respectively. We find that the fractional abundance of HC${}_3$N decreases from HMSCs to HMPOs using the Kolmogorov-Smirnov test. On the other hand, its average value of the column density slightly increases from HMSCs to HMPOs. This may imply that HC${}_3$N is newly formed in dense gas in HMPO regions. We also investigate the relationship between the column density of HC${}_3$N in HMPOs and the luminosity-to-mass ratio ($L/M$), a physical evolutional indicator. The column density of HC${}_3$N tends to decrease with increasing the $L/M$ ratio, which suggests that HC${}_3$N is destroyed by the stellar activities.

18 pages, 8 figures, 5 tables, Accepted by The Astrophysical Journal

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Cited by in corpus (26)

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• Long-Range Complex in the HC3N + CN Potential Energy Surface: Ab Initio Calculations and Intermolecular Potential
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• The TMRT K Band Observations towards 26 Infrared Dark Clouds: NH${}_3$, CCS, and HC${}_3$N
• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -- X. Chemical differentiation among the massive cores in G9.62+0.19