DC${}_3$N observations towards high-mass star-forming regions

Abstract

We present the study of deuteration of cyanoacetylene (HC${}_3$N) towards a sample of 28 high-mass star-forming cores divided into different evolutionary stages, from starless to evolved protostellar cores. We report for the first time the detection of DC${}_3$N towards 15 high-mass cores. The abundance ratios of DC${}_3$N with respect HC${}_3$N range in the interval 0.003$-$0.022, lower than those found in low-mas protostars and dark clouds. No significant trend with the evolutionary stage, or with the kinetic temperature of the region, has been found. We compare the level of deuteration of HC${}_3$N with those of other molecules towards the same sample, finding weak correlation with species formed only or predominantly in gas phase (N${}_2$H${}^{+}$ and HNC, respectively), and no correlation with species formed only or predominantly on dust grains (CH${}_3$OH and NH${}_3$, respectively). We also present a single-dish map of DC${}_3$N towards the protocluster IRAS 05358+3543, which shows that DC${}_3$N traces an extended envelope ($\sim$0.37 pc) and peaks towards two cold condensations separated from the positions of the protostars and the dust continuum. The observations presented in this work suggest that deuteration of HC${}_3$N is produced in the gas of the cold outer parts of massive star-forming clumps, giving us an estimate of the deuteration factor prior to the formation of denser gas.

Accepted in Monthly Notices of the Royal Astronomical Society -- 11 pages, 7 Figures, 2 Tables. Version with some typos corrected

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• Multi-line (sub)millimetre observations of the high-mass proto cluster IRAS 05358+3543
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• 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-
• ${}^{13}$C isotopic fractionation of HC${}_3$N in two starless cores: L1521B and L134N (L183)
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• First interferometric study of enhanced N-fractionation in N${}_2$H${}^{+}$: the high-mass star-forming region IRAS 05358+3543

Cited by in corpus (5)

• Chemical Differentiation around Five Massive Protostars Revealed by ALMA -Carbon-Chain Species, Oxygen-/Nitrogen-Bearing Complex Organic Molecules-
• The TOPGöt high-mass star-forming sample. I. Methyl cyanide emission as tracer of early phases of star formation
• Extensive ro-vibrational analysis of deuterated-cyanoacetylene (DC${}_3$N) from millimeter-wavelengths to the infrared domain
• Spatial distribution of NH2D in massive star-forming regions
• CHemical Evolution in MassIve star-forming COres (CHEMICO). I. Evolution of the temperature structure