Carbon Chain Chemistry in Hot-Core Regions around Three Massive Young Stellar Objects Associated with 6.7 GHz Methanol Masers

Abstract

We have carried out observations of CCH ($N=1-0$), CH${}_3$CN ($J=5-4$), and three ${}^{13}$C isotopologues of HC${}_3$N ($J=10-9$) toward three massive young stellar objects (MYSOs), G12.89+0.49, G16.86--2.16, and G28.28--0.36, with the Nobeyama 45-m radio telescope. Combined with previous results on HC${}_5$N, the column density ratios of $N$(CCH)/$N$(HC${}_5$N), hereafter the CCH/HC${}_5$N ratios, in the MYSOs are derived to be $\sim 15$. This value is lower than that in a low-mass warm carbon chain chemistry (WCCC) source by more than one order of magnitude. We compare the observed CCH/HC${}_5$N ratios with hot-core model calculations (Taniguchi et al. 2019). The observed ratios in the MYSOs can be best reproduced by models when the gas temperature is $\sim 85$ K, which is higher than in L1527, a low-mass WCCC source ($\sim 35$ K). These results suggest that carbon-chain molecules detected around the MYSOs exist at least partially in higher temperature regions than those in low-mass WCCC sources. There is no significant difference in column density among the three ${}^{13}$C isotopologues of HC${}_3$N in G12.89+0.49 and G16.86-2.16, while HCC${}^{13}$CN is more abundant than the others in G28.28--0.36. We discuss carbon-chain chemistry around the three MYSOs based on the CCH/HC${}_5$N ratio and the ${}^{13}$C isotopic fractionation of HC${}_3$N.

arXiv commentAccepted by The Astrophysical Journal, 17 pages, 6 figures, 6 tables

References in corpus (37)

• A computer program for fast non-LTE analysis of interstellar line spectra
• Complex Chemistry in Star-Forming Regions: An Expanded Gas-Grain Warm-up Chemical Model
• Formation of methyl formate and other organic species in the warm-up phase of hot molecular cores
• A Catalog of Extended Green Objects (EGOs) in the GLIMPSE Survey: A new sample of massive young stellar object outflow candidates
• 2018 Census of Interstellar, Circumstellar, Extragalactic, Protoplanetary Disk, and Exoplanetary Molecules
• A Geometric Determination of the Distance to the Galactic Center
• Gas and grain chemical composition in cold cores as predicted by the Nautilus 3-phase model
• Formation of complex organic molecules in cold objects: the role of gas phase reactions
• Astrochemistry During the Formation of Stars
• The Physical and Chemical Structure of Hot Molecular Cores
• Protostars: Forges of cosmic rays?
• A CH3CN and HCO+ survey towards southern methanol masers associated with star formation
• Modeling the Lukewarm Corino Phase - is L1527 unique?
• SOLIS II. Carbon-chain growth in the Solar-type protocluster OMC2-FIR4
• VLA observations of ammonia in high-mass star formation regions
• Trigonometric Parallaxes of Massive Star Forming Regions: G012.88+0.48 and W33
• Unveiling the physical conditions of the youngest disks: A warm embedded disk in L1527
• Interstellar dimethyl ether gas-phase formation: a quantum chemistry and kinetics study
• A systematic TMRT observational study of Galactic ${}^{12}$C/${}^{13}$C ratios from Formaldehyde
• Deep Very Large Array Radio Continuum Surveys of GLIMPSE Extended Green Objects (EGOs)
• SOLIS IV. Hydrocarbons in the OMC-2 FIR 4 region, a probe of energetic particle irradiation of the region
• The almost ubiquitous association of 6.7 GHz methanol masers with dust
• Chemical segregation of complex organic O-bearing species in Orion KL
• Detection of HC${}_5$N and HC${}_7$N Isotopologues in TMC-1 with the Green Bank Telescope
• Cyanopolyyne Chemistry around Massive Young Stellar Objects
• Implication of Formation Mechanisms of HC5N in TMC-1 as Studied by 13C Isotopic Fractionation
• 13C Isotopic Fractionation of HC3N in Star-Forming Regions -Low-Mass Star Forming Region L1527 and High-Mass Star Forming Region G28.28-0.36-
• Survey Observations to Study Chemical Evolution from High-mass Starless Cores to High-mass Protostellar Objects I: HC3N and HC5N
• An unbiased spectral line survey observation toward the low-mass star-forming region L1527
• ${}^{13}$C isotopic fractionation of HC${}_3$N in two starless cores: L1521B and L134N (L183)
• Chemical Diversity in Three Massive Young Stellar Objects associated with 6.7 GHz CH${}_3$OH Masers
• Ammonia and CO Outflow around 6.7 GHz Methanol Masers
• ${}^{13}$C Isotopic Fractionation of CCH in Two Starless Cores: L1521B and L134N
• Observations of Cyanopolyynes toward Four High-Mass Star-Forming Regions Containing Hot Cores
• Interferometric Observations of Cyanopolyynes toward the G28.28-0.36 High-Mass Star-Forming Region
• New detections of HC${}_5$N toward hot cores associated with 6.7 GHz methanol masers
• SMA observations of C2H in High-Mass Star Forming Regions

Cited by in corpus (7)

• Carbon-Chain Chemistry in the Interstellar Medium
• Chemical Differentiation around Five Massive Protostars Revealed by ALMA -Carbon-Chain Species, Oxygen-/Nitrogen-Bearing Complex Organic Molecules-
• Vibrationally-excited Lines of HC${}_3$N Associated with the Molecular Disk around the G24.78+0.08 A1 Hyper-compact H${}_{\mathrm{II}}$ Region
• Carbon-Chain Chemistry vs. Complex-Organic-Molecule Chemistry in Envelopes around Three Low-Mass Young Stellar Objects in the Perseus Region
• The SOFIA Massive (SOMA) Star Formation Q-band follow-up I. Carbon-chain chemistry of intermediate-mass protostars
• Chemical compositions in the vicinity of protostars in Ophiuchus
• CHemical Evolution in MassIve star-forming COres (CHEMICO). I. Evolution of the temperature structure