English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We carried out survey observations of HC$_{3}$N and HC$_{5}$N in the 42$-$45GHz band toward 17 high-mass starless cores (HMSCs) and 35 high-massprotostellar objects (HMPOs) with the Nobeyama 45 m radio telescope. We havedetected HC$_{3}$N from 15 HMSCs and 28 HMPOs, and HC$_{5}$N from 5 HMSCs and14 HMPOs, respectively. The average values of the column density of HC$_{3}$Nare found to be ($5.7 \pm 0.7$)$\times 10^{12}$ and ($1.03 \pm 0.12$)$\times10^{13}$ cm$^{-2}$ in HMSCs and HMPOs, respectively. The average values of thefractional abundance of HC$_{3}$N are derived to be ($6.6 \pm 0.8$)$\times10^{-11}$ 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 fromHMSCs to HMPOs using the Kolmogorov-Smirnov test. On the other hand, itsaverage 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. Wealso investigate the relationship between the column density of HC$_{3}$N inHMPOs and the luminosity-to-mass ratio ($L/M$), a physical evolutionalindicator. The column density of HC$_{3}$N tends to decrease with increasingthe $L/M$ ratio, which suggests that HC$_{3}$N is destroyed by the stellaractivities.

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