SIMBAD references

We carried out survey observations of HC₃N and HC₅N 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 HC₃N from 15 HMSCs and 28 HMPOs, and HC₅N from 5 HMSCs and 14 HMPOs, respectively. The average values of the column density of HC₃N are found to be (5.7±0.7)×10¹² and (1.03±0.12)×10¹³ cm^–2 in HMSCs and HMPOs, respectively. The average values of the fractional abundance of HC₃N are derived to be (6.6±0.8)×10^–11 and (3.6±0.5)×10^–11 in HMSCs and HMPOs, respectively. We find that the fractional abundance of HC₃N 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 HC₃N is newly formed in dense gas in HMPO regions. We also investigate the relationship between the column density of HC₃N in HMPOs and the luminosity-to-mass ratio (L/M), a physical evolutional indicator. The column density of HC₃N tends to decrease with the increase of the L/M ratio, which suggests that HC₃N is destroyed by the stellar activities.