Chemical evolution of HC3N in dense molecular clouds

Yu, Nan; Wang, Junjie; Xu, Jin-Long

doi:10.1093/mnras/stz2431

Cited by 5 publications

(10 citation statements)

References 55 publications

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“…This trend is consistent with the proposed evolutionary trend of HC 3 N (e.g. Urquhart et al 2019;Yu et al 2019) under the assumption that our Maser-only, Maser-RRL, and RRL-only sources correspond to YSOs, UC Hii regions, and normal classical Hii regions, respectively. 4.…”

Section: Discussionsupporting

confidence: 90%

“…Urquhart et al (2019) carried out a 3mm molecular-line survey towards a large sample consisting of 570 high-mass starforming clumps and found a trend in the detection rate of HC 3 N (J = 10-9), namely an increase from quiescent, to protostellar, to YSO, and then a slight decrease in Hii region (including all Hii region stages). Yu et al (2019) subdivided Hii regions into ultra-compact (UC) Hii regions and normal classical Hii regions. By analysing the archival available data from the Hi-GAL and the Millimetre Astronomy Legacy Team Survey at 90 GHz (MALT90) 9 , these latter authors found that the abundance of HC 3 N could increase in UC Hii regions, while it decreases or reaches a plateau in normal classical Hii regions.…”

Section: Evolution Of Hc 3 Nmentioning

confidence: 99%

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Cyanopolyyne line survey towards high-mass star-forming regions with TMRT

Wang,

Zhang,

Yan

et al. 2022

Preprint

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Context. Cyanopolyynes (HC 2n+1 N, n = 1,2,3), which are the linear carbon chain molecules, are precursors for the prebiotic synthesis of simple amino acids. They are important for understanding prebiotic chemistry and may be good tracers of the star formation sequence. Aims. We aim to search for cyanopolyynes in high-mass star-forming regions (HMSFRs) at possibly different evolutionary stages, investigate the evolution of HC 3 N and its relation with shock tracers, and detect the existence of HC 5 N and HC 7 N in HMSFRs with a formed protostar. Methods. We carried out a cyanopolyyne line survey towards a large sample of HMSFRs using the Shanghai Tian Ma 65m Radio Telescope (TMRT). Our sample consisted of 123 targets taken from the TMRT C band line survey. It included three kinds of sources, namely those with detection of the 6.7 GHz CH 3 OH maser alone, with detection of the radio recombination line (RRL) alone, and with detection of both (hereafter referred to as Maser-only, RRL-only, and Maser-RRL sources, respectively). For our sample with detection of cyanopolyynes, their column densities were derived using the rotational temperature measured from the NH 3 lines. We constructed and fitted the far-infrared (FIR) spectral energy distributions (SED; obtained from the Herschel FIR data and the Atacama Pathfinder Experiment data at 870 µm) of our HC 3 N sources. Moreover, by analysing the relation between HC 3 N and other shock tracers, we also investigate whether HC 3 N is a good tracer of shocks. Results. We detected HC 3 N in 38 sources, HC 5 N in 11 sources, and HC 7 N in G24.790+0.084, with the highest detection rate being found for Maser-RRL sources and a very low detection rate found for RRL-only sources. The mean column density of HC 3 N was found to be (1.75±0.42)×10 13 , (2.84±0.47)×10 13 , and (0.82±0.15)×10 13 cm −2 for Maser-only, Maser-RRL, and RRL-only sources, respectively. Based on a fit of the FIR SED, we derive their dust temperatures, H 2 column densities, and abundances of cyanopolyynes relative to H 2 . The mean relative abundance of HC 3 N was found to be (1.22±0.52)×10 −10 for Maser-only, (5.40±1.45)×10 −10 for Maser-RRL, and (1.65±1.50)×10 −10 for RRL-only sources, respectively. Conclusions. The detection rate, the column density, and the relative abundance of HC 3 N increase from Maser-only to Maser-RRL sources and decrease from Maser-RRL to RRL-only sources. This trend is consistent with the proposed evolutionary trend of HC 3 N under the assumption that our Maser-only, Maser-RRL, and RRL-only sources correspond to massive young stellar objects, ultracompact Hii regions, and normal classical Hii regions, respectively. Our detections enlarge the sample of HC 3 N in HMSFRs and support the idea that unsaturated complex organic molecules can exist in HMSFRs with a formed protostar. Furthermore, a statistical analysis of the integrated line intensity and column density of HC 3 N and shock-tracing molecules (SiO, H 2 CO) enabled us to find positive correlations between them. This suggests th...

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Section: Discussionsupporting

confidence: 90%

Section: Evolution Of Hc 3 Nmentioning

confidence: 99%

Cyanopolyyne line survey towards high-mass star-forming regions with TMRT

Wang,

Zhang,

Yan

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…Urquhart et al ( 2019) carried out a 3 mm molecular-line survey towards a large sample consisting of 570 high-mass starforming clumps and found a trend in the detection rate of HC 3 N (J = 10-9), namely an increase from quiescent, to protostellar, to YSO, and then a slight decrease in HII region (including all HII region stages). Yu et al (2019) subdivided HII regions into ultra-compact (UC) HII regions and normal classical HII regions. By analysing the archival available data from the Hi-GAL and the Millimetre Astronomy Legacy Team Survey at 90 GHz (MALT90) 9 , these latter authors found that the abundance of HC 3 N could increase in UC HII regions, while it decreases or reaches a plateau in normal classical HII regions.…”

Section: Evolution Of Hc 3 Nmentioning

confidence: 99%

“…Cyanoacetylene (HC 3 N), which is the shortest cyanopolyyne molecule, normally exists in warm and active star-forming regions (e.g. Yu et al 2019;Feng et al 2021). The University of Manchester Institute of Science and Technology (UMIST) database for astrochemistry 2 suggests that HC 3 N has four main formation pathways, including the neutral-neutral reaction between C 2 H 2 and CN, the neutral-neutral reaction between C 2 H and HNC, the ion-molecule reaction between C 3 H + n (n = 3-5) and nitrogen atoms, and the ion-molecule reaction between C 2 H + 2 and HCN (McElroy et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Cyanopolyyne line survey towards high-mass star-forming regions with TMRT

Wang

Zhang

Yan

et al. 2022

A&A

View full text Add to dashboard Cite

Context. Cyanopolyynes (HC2n+1 N, n = 1,2,3), which are the linear carbon chain molecules, are precursors for the prebiotic synthesis of simple amino acids. They are important for understanding prebiotic chemistry and may be good tracers of the star formation sequence. Aims. We aim to search for cyanopolyynes in high-mass star-forming regions (HMSFRs) at possibly different evolutionary stages, investigate the evolution of HC3N and its relation with shock tracers, and detect the existence of HC5N and HC7N in HMSFRs with a formed protostar. Methods. We carried out a cyanopolyyne line survey towards a large sample of HMSFRs using the Shanghai Tian Ma 65 m Radio Telescope (TMRT). Our sample consisted of 123 targets taken from the TMRT C band line survey. It included three kinds of sources, namely those with detection of the 6.7 GHz CH3OH maser alone, with detection of the radio recombination line (RRL) alone, and with detection of both (hereafter referred to as Maser-only, RRL-only, and Maser-RRL sources, respectively). For our sample with detection of cyanopolyynes, their column densities were derived using the rotational temperature measured from the NH3 lines. We constructed and fitted the far-infrared (FIR) spectral energy distributions (SED; obtained from the Herschel FIR data and the Atacama Pathfinder Experiment data at 870 µm) of our HC3N sources. Moreover, by analysing the relation between HC3N and other shock tracers, we also investigate whether HC3N is a good tracer of shocks. Results. We detected HC3N in 38 sources, HC5N in 11 sources, and HC7N in G24.790+0.084, with the highest detection rate being found for Maser-RRL sources and a very low detection rate found for RRL-only sources. The mean column density of HC3N was found to be (1.75 ± 0.42) × 1013, (2.84 ± 0.47) × 1013, and (0.82 ± 0.15) × 1013 cm−2 for Maser-only, Maser-RRL, and RRL-only sources, respectively. Based on a fit of the FIR SED, we derive their dust temperatures, H2 column densities, and abundances of cyanopolyynes relative to H2. The mean relative abundance of HC3N was found to be (1.22 ± 0.52) × 10−10 for Maser-only, (5.40 ± 1.45) × 10−10 for Maser-RRL, and (1.65 ± 1.50) × 10−10 for RRL-only sources, respectively. Conclusions. The detection rate, the column density, and the relative abundance of HC3N increase from Maser-only to Maser-RRL sources and decrease from Maser-RRL to RRL-only sources. This trend is consistent with the proposed evolutionary trend of HC3N under the assumption that our Maser-only, Maser-RRL, and RRL-only sources correspond to massive young stellar objects, ultracompact H ii regions, and normal classical H ii regions, respectively. Our detections enlarge the sample of HC3N in HMSFRs and support the idea that unsaturated complex organic molecules can exist in HMSFRs with a formed protostar. Furthermore, a statistical analysis of the integrated line intensity and column density of HC3N and shock-tracing molecules (SiO, H2CO) enabled us to find positive correlations between them. This suggests that HC3N may be another tracer of shocks, and should therefore be the subject of further observations and corresponding chemical simulations. Our results indirectly support the idea that the neutral-neutral reaction between C2H2 and CN is the dominant formation pathway of HC3N.

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“…of the chemical evolution of molecular clouds [5] or -through the DC 3 N isotopologue -as proxy of the deuteration level prior to the formation of dense gas in star-forming regions [6]. Moreover, cyanoacetylene emission has been used to unravel the seasonal changes and atmospheric dynamics of the largest Saturn's moon Titan [7] and is predicted to be detectable in Super-Earth atmospheres by upcoming James Webb Telescope observations [8].…”

Section: Introductionmentioning

confidence: 99%