TMRT OBSERVATIONS OF CARBON-CHAIN MOLECULES IN SERPENS SOUTH 1a

Li, Juan; Shen, Zhi-Qiang; Wang, Junzhi; Chen, Xi; Wu, Yajun; Zhao, Rong-Bing; Wang, Jinqing; Zuo, Xiuting; Fan, Qingyuan; Hong, Xiaoyu; Jiang, Dongrong; Li, Bin; Liang, Shiguang; Ling, Quan-Bao; Liu, Qinghui; Qian, Zhihan; Zhang, Xiuzhong; Zhong, Wang; Ye, Shuhua

doi:10.3847/0004-637x/824/2/136

Cited by 39 publications

(44 citation statements)

References 48 publications

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“…Regarding the abundance ratio of a source previously detected with the TMRT, Serpens South 1a (Li et al 2016), the x(HC 3 N)/x(HC 5 N) and x(HC 5 N)/x(HC 7 N) ratios are 6.5 and 2.0 respectively, and 4.3 on the average, which is close to those of the Lup I starless cores. The ratio of x(C 3 S)/x(HC 7 N) is 1.0 which is larger than those of all the Lup I cores.…”

Section: Lupus I Starless Dust Coressupporting

confidence: 57%

“…The observations were carried out with the Tian Ma Radio Telescope (TMRT) of the Shanghai Observatory. The TMRT is a newly built 65-m diameter fully steerable radio telescope located in the western outskirts of Shanghai (Li et al 2016). The pointing accuracy is better than 10 , and the main beam efficiency is 0.60 in the 12-18 GHz band (Wang et al 2015b;Li et al 2016).…”

Section: Observationmentioning

confidence: 99%

“…The metal abundances were adopted as the low-metal abundance case of Graedel et al (1982), except for that of sulfur. In star-forming regions, the total abundance of sulfur-bearing species is ∼ 10 −8 (Li et al 2016), and this value was adopted instead of the widely used 8 × 10 −8 (Lee et al 1998). All the elements were initially ionized except for the hydrogen atoms.…”

Section: Model Testmentioning

confidence: 99%

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Carbon-chain molecules in molecular outflows and Lupus I region – new producing region and new forming mechanism

Liu

Chen

et al. 2019

Monthly Notices of the Royal Astronomical Society

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Using the new equipment of the Shanghai Tian Ma Radio Telescope, we have searched for carbon-chain molecules (CCMs) towards five outflow sources and six Lupus I starless dust cores, including one region known to be characterized by warm carbon-chain chemistry (WCCC), Lupus I-1 (IRAS 15398-3359), and one TMC-1 like cloud, Lupus I-6 (Lupus-1A). Lines of HC 3 N J = 2−1, HC 5 N J = 6−5, HC 7 N J = 14−13, 15−14, 16−15 and C 3 S J = 3−2 were detected in all the targets except in the outflow source L1660 and the starless dust core Lupus I-3/4. The column densities of nitrogen-bearing species range from 10 12 to 10 14 cm −2 and those of C 3 S are about 10 12 cm −2 . Two outflow sources, I20582+7724 and L1221, could be identified as new carbon-chain-producing regions. Four of the Lupus I dust cores are newly identified as early quiescent and dark carbon-chain-producing regions similar to Lup I-6, which together with the WCCC source, Lup I-1, indicate that carbon-chain-producing regions are popular in Lupus I which can be regard as a Taurus like molecular cloud complex in our Galaxy. The column densities of C 3 S are larger than those of HC 7 N in the three outflow sources I20582, L1221 and L1251A. Shocked carbon-chain chemistry (SCCC) is proposed to explain the abnormal high abundances of C 3 S compared with those of nitrogen-bearing CCMs. Gas-grain chemical models support the idea that shocks can fuel the environment of those sources with enough S + thus driving the generation of S-bearing CCMs.

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Section: Lupus I Starless Dust Coressupporting

confidence: 57%

Section: Observationmentioning

confidence: 99%

Section: Model Testmentioning

confidence: 99%

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Carbon-chain molecules in molecular outflows and Lupus I region – new producing region and new forming mechanism

Liu

Chen

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…This kind of anomaly, known as isotopic fractionation, has been reported and studied, not only in HC3N but also in HC5N and other carbon-chain molecules, in several hot and cold sources (e.g. Takano et al 1998;Sakai et al 2007Sakai et al , 2013Li et al 2016;Araki et al 2016;Taniguchi et al 2016aTaniguchi et al ,b, 2017. The relative abundances ratios of the 13 C isotopologues can be also calculated using column densities estimated from the most conspicuous transitions assuming LTE conditions (see Table 2).…”

Section: Isotopic Fractionation and Astrochemical Implicationsmentioning

confidence: 92%

Cyanoacetylene in the outflow/hot molecular core G331.512−0.103

Duronea

Bronfman

Mendoza³

et al. 2019

Monthly Notices of the Royal Astronomical Society

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Using APEX-1 and APEX-2 observations, we have detected and studied the rotational lines of the HC 3 N molecule (cyanoacetylene) in the powerful outflow/hot molecular core G331.512-0.103. We identified thirty-one rotational lines at J levels between 24 and 39; seventeen of them in the ground vibrational state v=0 (9 lines corresponding to the main C isotopologue and 8 lines corresponding to the 13 C isotopologues), and fourteen in the lowest vibrationally excited state v 7 =1. Using LTE-based population diagrams for the beam-diluted v=0 transitions, we determined T exc =85±4 K and N (HC 3 N)=(6.9±0.8)×10 14 cm −2 , while for the beam-diluted v 7 =1 transitions we obtained T exc =89±10 K and N (HC 3 N)=2±1×10 15 cm −2 . Non-LTE calculations using H 2 collision rates indicate that the HC 3 N emission is in good agreement with LTE-based results. From the non-LTE method we estimated T kin ≃90 K, n(H 2 )≃2×10 7 cm −3 for a central core of 6 arcsec in size. A vibrational temperature in the range from 130 K to 145 K was also determined, values which are very likely lower limits. Our results suggest that rotational transitions are thermalized, while IR radiative pumping processes are probably more efficient than collisions in exciting the molecule to the vibrationally excited state v 7 =1. Abundance ratios derived under LTE conditions for the 13 C isotopologues suggest that the main formation pathway of HC 3 N is C 2 H 2 + CN → HC 3 N + H.

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“…All these cores in the molecular complex Taurus are in an early stage of CCM chemistry. Meanwhile a number of starless cores outside of Taurus, such as L492, Lupus-1A, L1512, and Serpens South 1a (Serp S1a), have been found to be abundant carbon-chain-producing regions (Hirota & Yamamoto 2006;Sakai et al 2010b;Cordiner et al 2011;Friesen et al 2013;Li et al 2016). Starless and dark cores CB 130-3 in the Aquila rift region and L673-SMM4 in Cloud B of L673 were also identified as carbon-chain-producing regions (Hirota et al 2011).…”

Section: Introductionmentioning

confidence: 99%

A particular carbon-chain-producing region: L1489 starless core

Lin

Liu

et al. 2019

A&A

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We detected carbon-chain molecules (CCMs) HC 2n+1 N (n=1-3) and C 3 S in K u band as well as high-energy excitation lines including C 4 H N=9-8, J=17/2-15/2, 19/2-17/2, and CH 3 CCH J=5-4, K=2 in the 3 mm band toward a starless core called the eastern molecular core (EMC) of L1489 IRS. Maps of all the observed lines were also obtained. Comparisons with a number of early starless cores and WCCC source L1527 show that the column densities of C 4 H and CH 3 CCH are close to those of L1527, and the CH 3 CCH column densities of the EMC and L1527 are slightly higher than those of TMC-1. The EMC and L1527 have similar C 3 S column densities, but they are much lower than those of all the starless cores, with only 6.5% and 10% of the TMC-1 value, respectively. The emissions of the N-bearing species of the EMC and L1527 are at the medium level of the starless cores. These comparisons show that the CCM emissions in the EMC are similar to those of L1527, though L1527 contains a protostar. Although dark and quiescent, the EMC is warmer and at a later evolutionary stage than classical carbon-chain-producing regions in the cold, dark, quiescent early phase. The PACS, SPIRE, and SCUBA maps evidently show that the L1489 IRS seems to be the heating source of the EMC. Although it is located at the margins of the EMC, its bolometric luminosity and bolometric temperature are relatively high. Above all, the EMC is a rather particular carbon-chain-producing region and is quite significant for CCM science.

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TMRT OBSERVATIONS OF CARBON-CHAIN MOLECULES IN SERPENS SOUTH 1a

Cited by 39 publications

References 48 publications

Carbon-chain molecules in molecular outflows and Lupus I region – new producing region and new forming mechanism

Carbon-chain molecules in molecular outflows and Lupus I region – new producing region and new forming mechanism

Cyanoacetylene in the outflow/hot molecular core G331.512−0.103

A particular carbon-chain-producing region: L1489 starless core

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