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

2019 ◽  
Vol 488 (1) ◽  
pp. 495-511
Author(s):  
Yuefang Wu ◽  
Xunchuan Liu ◽  
Xi Chen ◽  
Lianghao Lin ◽  
Jinghua Yuan ◽  
...  
Keyword(s):  
Radio Telescope ◽  
Molecular Cloud ◽  
Carbon Chain ◽  
Species Range ◽  
Chain Molecules ◽  
Forming Mechanism ◽  
Molecular Outflows ◽  
Chemical Models ◽  
Cloud Complex

Abstract 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 HC3N J = 2 − 1, HC5N J = 6 − 5, HC7N J = 14 − 13, 15 − 14, 16 − 15, and C3S 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 1012 to 1014 cm−2 and those of C3S are about 1012 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 C3S are larger than those of HC7N in the three outflow sources I20582, L1221, and L1251A. Shocked carbon-chain chemistry is proposed to explain the abnormal high abundances of C3S 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.

Mapping observations of sulfur-containing carbon-chain molecules in Taurus Molecular Cloud 1 (TMC-1)

1992 ◽  
Vol 394 ◽  
pp. 539 ◽  
Author(s):  
Yasuhiro Hirahara ◽  
Hiroko Suzuki ◽  
Satoshi Yamamoto ◽  
Kentarou Kawaguchi ◽  
Norio Kaifu ◽  
...  
Keyword(s):  
Molecular Cloud ◽  
Carbon Chain ◽  
Chain Molecules ◽  
Sulfur Containing ◽  
Taurus Molecular Cloud

scholarly journals Hunting for hot corinos and WCCC sources in the OMC-2/3 filament

2020 ◽  
Vol 636 ◽  
pp. A19 ◽  
Author(s):  
M. Bouvier ◽  
A. López-Sepulcre ◽  
C. Ceccarelli ◽  
C. Kahane ◽  
M. Imai ◽  
...  
Keyword(s):  
Molecular Cloud ◽  
Chemical Nature ◽  
Line Emission ◽  
Carbon Chain ◽  
Abundance Ratio ◽  
High Angular Resolution ◽  
Chain Molecules ◽  
Ethynyl Radical ◽  
Birth Environment ◽  
Complex Organic

Context. Solar-like protostars are known to be chemically rich, but it is not yet clear how much their chemical composition can vary and why. So far, two chemically distinct types of Solar-like protostars have been identified: hot corinos, which are enriched in interstellar Complex Organic Molecules, such as methanol (CH3OH) or dimethyl ether (CH3OCH3), and warm carbon chain chemistry (WCCC) objects, which are enriched in carbon chain molecules, such as butadiynyl (C4H) or ethynyl radical (CCH). However, none of these have been studied so far in environments similar to that in which our Sun was born, that is, one that is close to massive stars. Aims. In this work, we search for hot corinos and WCCC objects in the closest analogue to the Sun’s birth environment, the Orion Molecular Cloud 2/3 (OMC-2/3) filament located in the Orion A molecular cloud. Methods. We obtained single-dish observations of CCH and CH3OH line emission towards nine Solar-like protostars in this region. As in other similar studies of late, we used the [CCH]/[CH3OH] abundance ratio in order to determine the chemical nature of our protostar sample. Results. Unexpectedly, we found that the observed methanol and ethynyl radical emission (over a few thousands au scale) does not seem to originate from the protostars but rather from the parental cloud and its photo-dissociation region, illuminated by the OB stars of the region. Conclusions. Our results strongly suggest that caution should be taken before using [CCH]/[CH3OH] from single-dish observations as an indicator of the protostellar chemical nature and that there is a need for other tracers or high angular resolution observations for probing the inner protostellar layers.

scholarly journals Activity of the first interstellar comet 2I/Borisov around perihelion: results from Indian observatories

2021 ◽  
Vol 502 (3) ◽  
pp. 3491-3499
Author(s):  
K Aravind ◽  
Shashikiran Ganesh ◽  
Kumar Venkataramani ◽  
Devendra Sahu ◽  
Dorje Angchuk ◽  
...  
Keyword(s):  
Solar System ◽  
Production Rate ◽  
Rate Ratio ◽  
Carbon Chain ◽  
Astronomical Observatory ◽  
Nucleus Size ◽  
Chain Molecules ◽  
Molecular Emission ◽  
Imaging And Spectroscopy ◽  
Gas Ratio

ABSTRACT Comet 2I/Borisov is the first true interstellar comet discovered. Here, we present results from observational programs at two Indian observatories, 2 m Himalayan Chandra Telescope at the Indian Astronomical Observatory, Hanle (HCT) and 1.2 m telescope at the Mount Abu Infrared Observatory (MIRO). Two epochs of imaging and spectroscopy were carried out at the HCT and three epochs of imaging at MIRO. We found CN to be the dominant molecular emission on both epochs, 2019 November 30 and December 22, at distances of rH = 2.013 and 2.031 au, respectively. The comet was inferred to be relatively depleted in Carbon bearing molecules on the basis of low C2 and C3 abundances. We find the production rate ratio, Q(C2)/Q(CN) = 0.54 ± 0.18, pre-perihelion and Q(C2)/Q(CN) = 0.34 ± 0.12 post-perihelion. This classifies the comet as being moderately depleted in carbon chain molecules. Using the results from spectroscopic observations, we believe the comet to have a chemically heterogeneous surface having variation in abundance of carbon chain molecules. From imaging observations, we infer a dust-to-gas ratio similar to carbon chain depleted comets of the Solar system. We also compute the nucleus size to be in the range 0.18 km ≤ r ≤ 3.1 km. Our observations show that 2I/Borisov’s behaviour is analogous to that of the Solar system comets.

scholarly journals Herschelfar-IR observations of the Chamaeleon molecular cloud complex

2012 ◽  
Vol 545 ◽  
pp. A145 ◽  
Author(s):  
E. Winston ◽  
N. L. J. Cox ◽  
T. Prusti ◽  
B. Merín ◽  
A. Ribas ◽  
...  
Keyword(s):  
Molecular Cloud ◽  
Cloud Complex

scholarly journals The H II region-molecular cloud complex W3 - Observations of CO, CS, and HCN

1980 ◽  
Vol 237 ◽  
pp. 711 ◽  
Author(s):  
H. R. Dickel ◽  
J. R. Dickel ◽  
W. J. Wilson ◽  
M. W. Werner
Keyword(s):  
Molecular Cloud ◽  
H Ii Region ◽  
Cloud Complex

Ion-molecule reactions with carbon chain molecules: reactions with diacetylene and the diacetylene cation

1986 ◽  
Vol 64 (4) ◽  
pp. 641-648 ◽  
Author(s):  
Seksan Dheandhanoo ◽  
Leonard Forte ◽  
Arnold Fox ◽  
Diethard K. Bohme
Keyword(s):  
Carbon Chain ◽  
Heat Of Formation ◽  
Buffer Gas ◽  
Proton Affinities ◽  
Chain Molecules ◽  
Ion Flow ◽  
Molecule Reaction ◽  
Ion Molecule Reactions ◽  
A Value ◽  
Selected Ion Flow Tube

Reactions of hydrocarbon and carbon/nitrogen ions with diacetylene and of the diacetylene radical cation with various molecules have been examined with a view to molecular growth by ion–molecule reaction. Measurements were performed with a Selected-Ion Flow Tube (SIFT) apparatus at 296 ± 2 K of the rate constants and product distributions for the reactions of C+, CH3+, C2H2+, C3H+, CN+, C2N+, and C2N2+ with C4H2 and of C4H2+ with H2, CO, C2H2, C2N2, and C4H2. Condensation and association reactions which build up the carbon content of the ion were observed to compete with charge transfer. For the reactions of CN+ and C2N2+ with C4H2 this growth involved the addition of cyanide to the carbon chain. The kinetics of protonation of diacetylene were also investigated. It was possible to bracket the proton affinity of diacetylene between the known proton affinities of HCN and CH3OH with a value for PA(C4H2) = 177 ± 5 kcal mol−1, which results in a heat of formation for C4H3+ of 305 ± 5 kcal mol−1. Numerous secondary association reactions were observed to form adduct ions in helium buffer gas at total pressures of a few tenths of a Torr with rates near the collision rate. This was the case for C6H4+ (C4H2+•C2H2), C7H5+ (C3H3+•C4H2), C8H4+ (C4H2+•C4H2), C8H5+ (C4H3+•C4H2), C9H3+ (C5H+•C4H2), C9H4+ (C5H2+•C4H2), C9H5 (C5H3+•C4H2), C10H4+ (C6H2+•C4H2), C10H5+ (C6H3+•C4H2), C11H7+ (C3H3+•(C4H2)2), C12H6+ (C4H2+•(C4H2)2), C9H3N+ (HC5N+•C4H2), and C10H4N+ (C2N+•(C4H2)2) where the reactants are indicated in parentheses. The observed high rates of association imply the formation of chemical bonds in the adduct ions but the structures of these ions were not resolved experimentally. In most instances there seems little basis for preferring acyclic over cyclic adduct ions.

The Perseus OB2 Superbubble and the Taurus-Auriga-California-Perseus Molecular Cloud Loop

2021 ◽  
Author(s):  
Xuepeng Chen ◽  
Weihua Guo ◽  
Jiangcheng Feng ◽  
Yang Su ◽  
Yan Sun ◽  
...  
Keyword(s):  
Atomic Hydrogen ◽  
Molecular Cloud ◽  
Three Dimensional ◽  
Solar Neighborhood ◽  
Dimensional Structure ◽  
Wide Field ◽  
Star Forming ◽  
Stellar Feedback ◽  
History Of ◽  
Cloud Complex

Abstract Located at a distance of about 300 pc, Perseus OB2 (or Per~OB2 for short) is one of the major OB associations in the solar vicinity\cite{Zeeuw99,Belikov2002}, which has blown a supershell with a diameter of about 15 degree seen in the atomic hydrogen line surveys\cite{Sancisi1974,Heiles1984,Hartmann1997}. It was long considered that stellar feedback from the Per~OB2 association had formed a superbubble that swept up the surrounding interstellar medium into the observed supershell\cite{Bally2008}. Here we report the three-dimensional structure of the Per~OB2 superbubble, based on wide-field atomic hydrogen and molecular gas (traced by CO) surveys. The measured diameter of the superbubble is roughly 330 pc. Multiple atomic hydrogen shells/loops with expansion velocities of about 10 km/s are revealed in the superbubble, suggesting a complicated evolution history of the superbubble. Furthermore, the inspections of the morphology, kinematics and timescale of the Taurus-Auriga, California, and Perseus molecular clouds shows that the cloud complex is a super molecular cloud loop circling around and co-expanding with the Per~OB2 superbubble. We conclude that the Taurus-Auriga-California-Perseus loop, the largest star-forming molecular cloud complex in the solar neighborhood, is formed from the feedback of the Per~OB2 superbubble.

Long Carbon Chain Molecules in the Laboratory and in Space

1980 ◽  
pp. 59-65 ◽  
Author(s):  
G. Winnewisser ◽  
F. Toelle ◽  
H. Ungerechts ◽  
C. M. Walmsley
Keyword(s):  
Carbon Chain ◽  
Chain Molecules

Observations of the 1→0 Transition of CO Towards Southern HII Regions

1982 ◽  
Vol 4 (4) ◽  
pp. 434-440 ◽  
Author(s):  
J. B. Whiteoak ◽  
Robina E. Otrupcek ◽  
C. J. Rennie
Keyword(s):  
Radio Telescope ◽  
Molecular Cloud ◽  
Milky Way ◽  
Line Emission ◽  
Hii Regions ◽  
Hii Region ◽  
Giant Molecular Cloud ◽  
Molecular Lines ◽  
Csiro Division

The 4-m radio telescope of the CSIRO Division of Radiophysics at Epping is being used to survey the line emission associated with the 1→0 transition of CO (rest frequency 115.271 GHz) in the southern Milky Way. The programme includes mapping the CO distribution across giant molecular-cloud/HII-region complexes. As a first stage the emission has been observed towards bright southern HII regions. These results will not only serve as a basis for future extensive mapping but will also provide data which is directly comparable with observations of other molecular lines that have been made towards the HII regions.

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