Evolutionary view through the starless cores in Taurus: deuteration in TMC 1-C and TMC 1-CP

Abstract

The chemical and physical evolution of starless and pre-stellar cores are of paramount importance to understanding the process of star formation. The Taurus Molecular Cloud cores TMC 1-C and TMC 1-CP share similar initial conditions and provide an excellent opportunity to understand the evolution of the pre-stellar core phase. We investigated the evolutionary stage of starless cores based on observations towards the prototypical dark cores TMC 1-C and TMC 1-CP, mapping them in the CS $3\to 2$, C${}^{34}$S $3\to 2$, ${}^{13}$CS $2\to 1$, DCN $1\to 0$, DCN $2\to 1$, DNC $1\to 0$, DNC $2\to 1$, DN${}^{13}$C $1\to 0$, DN${}^{13}$C $2\to 1$, N${}_2$H${}^{+}$ $1\to 0$, and N${}_2$D${}^{+}$ $1\to 0$ transitions. We performed a multi-transitional study of CS and its isotopologs, DCN, and DNC lines to characterize the physical and chemical properties of these cores. We studied their chemistry using the state-of-the-art gas-grain chemical code Nautilus and pseudo time-dependent models to determine their evolutionary stage. Observational diagnostics seem to indicate that TMC 1-C is in a later evolutionary stage than TMC 1-CP, with a chemical age $\sim$1 Myr. TMC 1-C shows signs of being an evolved core at the onset of star formation, while TMC 1-CP appears to be in an earlier evolutionary stage due to a more recent formation or, alternatively, a collapse slowed down by a magnetic support.

26 pages, 10 figures

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Cited by in corpus (15)

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• Gas phase Elemental abundances in Molecular cloudS (GEMS) V. Methanol in Taurus
• Multi-line observations of CH${}_3$OH, c-C${}_3$H${}_2$ and HNCO towards L1544: Dissecting the core structure with chemical differentiation
• Gas phase Elemental abundances in Molecular cloudS (GEMS) VI. A sulphur journey across star-forming regions: study of thioformaldehyde emission
• Linking the dust and chemical evolution: Taurus and Perseus -- New collisional rates for HCN, HNC, and their C, N, and H isotopologues
• Doubly substituted isotopologues of HCCCN in TMC-1: Detection of D13CCCN, DC13CCN, DCC13CN, DCCC15N, H13C13CCN, H13CC13CN, HC13C13CN, HCC13C15N, and HC13CC15N
• Evolution of Chemistry in the envelope of Hot Corinos (ECHOS). I. Extremely young sulphur chemistry in the isolated Class 0 object B335
• The initial magnetic criticality of prestellar cores
• Chemical variations across the TMC-1 boundary: molecular tracers from translucent phase to dense phase
• Magnetic field measurement in TMC-1C using 22.3 GHz CCS Zeeman splitting
• First detection of HS2 in a cold dark cloud
• Studying the chemical and kinematical structures of dense cores TMC-1C, L1544, and TMC-1 in the Taurus molecular cloud using the CCS and NH3 observations
• Gas-phase Elemental abundances in Molecular cloudS (GEMS) XI. The evolution of HCN, HNC, and N2H+ isotopic ratios in starless cores
• NIKA2 observations of starless cores in Taurus and Perseus
• An 18 - 25 GHz spectroscopic survey of southern hemisphere dense cores