Chemical evolution in the early phases of massive star formation II: Deuteration

Abstract

The chemical evolution in high-mass star-forming regions is still poorly constrained. Studying the evolution of deuterated molecules allows to differentiate between subsequent stages of high-mass star formation regions due to the strong temperature dependence of deuterium isotopic fractionation. We observed a sample of 59 sources including 19 infrared dark clouds, 20 high-mass protostellar objects, 11 hot molecular cores and 9 ultra-compact HII regions in the (3-2) transitions of the four deuterated molecules, DCN, DNC, DCO+ and N2D+ as well as their non-deuterated counterpart. The overall detection fraction of DCN, DNC and DCO+ is high and exceeds 50% for most of the stages. N2D+ was only detected in a few infrared dark clouds and high-mass protostellar objects. It can be related to problems in the bandpass at the frequency of the transition and to low abundances in the more evolved, warmer stages. We find median D/H ratios of ~0.02 for DCN, ~0.005 for DNC, ~0.0025 for DCO+ and ~0.02 for N2D+. While the D/H ratios of DNC, DCO+ and N2D+ decrease with time, DCN/HCN peaks at the hot molecular core stage. We only found weak correlations of the D/H ratios for N2D+ with the luminosity of the central source and the FWHM of the line, and no correlation with the H2 column density. In combination with a previously observed set of 14 other molecules (Paper I) we fitted the calculated column densities with an elaborate 1D physico-chemical model with time-dependent D-chemistry including ortho- and para-H2 states. Good overall fits to the observed data have been obtained the model. It is one of the first times that observations and modeling have been combined to derive chemically based best-fit models for the evolution of high-mass star formation including deuteration.

26 pages, 16 figures, accepted at A&A

References in corpus (8)

• The SCUBA Legacy Catalogue: Continuum Objects Detected by SCUBA
• Cooling, Gravity and Geometry: Flow-driven Massive Core Formation
• The N2D+/N2H+ ratio as an evolutionary tracer of Class 0 protostars
• Molecular Star Formation Rate Indicators in Galaxies
• Searching for massive pre--stellar cores through observations of N2H+ and N2D+
• Probing the initial conditions of High Mass Star formation -- I. Deuteration and depletion in high mass pre/protocluster clumps
• Dust and gas emission in the prototypical hot core G29.96-0.02 at sub-arcsecond resolution
• The Bolocam Galactic Plane Survey. XII. Distance Catalog Expansion Using Kinematic Isolation of Dense Molecular Cloud Structures With 13CO(1-0)

Cited by in corpus (32)

• An ALMA survey of DCN/H${}^{13}$CN and DCO${}^{+}$/H${}^{13}$CO${}^{+}$ in protoplanetary disks
• DCO${}^{+}$, DCN and N${}_2$D${}^{+}$ reveal three different deuteration regimes in the disk around the Herbig Ae star HD163296
• Chemical complexity in high-mass star formation: An observational and modeling case study of the AFGL 2591 VLA 3 hot core
• Molecules with ALMA at Planet-forming Scales (MAPS). X. Studying deuteration at high angular resolution toward protoplanetary disks
• The ALMA Survey of 70 $\mu \mathrm{m}$ Dark High-mass Clumps in Early Stages (ASHES). VII: Chemistry of Embedded Dense Cores
• Molecular Cloud Cores with High Deuterium Fraction: Nobeyama Single-Pointing Survey
• Gas phase Elemental abundances in Molecular cloudS (GEMS) VI. A sulphur journey across star-forming regions: study of thioformaldehyde emission
• Fragmentation and kinematics in high-mass star formation: CORE-extension targeting two very young high-mass star-forming regions
• Similar complex kinematics within two massive, filamentary infrared dark clouds
• Physical and chemical complexity in high-mass star-forming regions with ALMA. I. Overview and evolutionary trends of physical properties
• Clustered star formation at early evolutionary stages. Physical and chemical analysis of the young star-forming regions ISOSS J22478+6357 and ISOSS J23053+5953
• Deuterated ammonia in Galactic massive star-forming regions
• ALMA ACA and Nobeyama observations of two Orion cores in deuterated molecular lines
• Complex organic molecules uncover deeply embedded precursors of hot cores
• Molecular Cloud Cores with High Deuterium Fractions: Nobeyama Mapping Survey
• Fragmentation of the High-mass "Starless'' Core G10.21-0.31: a Coherent Evolutionary Picture for Star Formation
• Parsec-scale cosmic-ray ionisation rate in Orion
• Variations of the HCO${}^{+}$, HCN, HNC, N${}_2$H${}^{+}$ and NH${}_3$ deuterium fractionation in high-mass star-forming regions
• A new analytic approach to infer the cosmic-ray ionization rate in hot molecular cores from HCO${}^{+}$, N${}_2$H${}^{+}$, and CO observations
• Deuterium Fractionation across the Infrared Dark Cloud G034.77-00.55 interacting with the Supernova Remnant W44
• Illuminating a tadpole's metamorphosis II: observing the on-going transformation with ALMA
• The physical and chemical structure of high-mass star-forming regions. Unraveling chemical complexity with the NOEMA large program "CORE"
• Radial variations in nitrogen, carbon, and hydrogen fractionation in the PDS 70 planet-hosting disk
• A Possible Chemical Clock in High-mass Star-forming Regions: N(HC3N)/N(N2H+)?
• Molecular deuterations in massive Starless Clump Candidates
• DCO${}^{+}$ and DCN 1-0 survey toward a sample of Planck cold clumps
• The LMT 2 millimeter receiver system (B4R). II. Science demonstration observations toward Orion-KL/OMC-1
• The kinematics of the magnetised protostellar core IRAS15398-3359
• Chemical complexity in star formation induced by stellar feedback: cores shock-formed by the supernova remnant W44
• The TMRT K Band Observations towards 26 Infrared Dark Clouds: NH${}_3$, CCS, and HC${}_3$N
• First detection of a deuterated molecule in a starburst environment within NGC 253
• The Cygnus Allscale Survey of Chemistry and Dynamical Environments: CASCADE III. The large scale distribution of DCO+, DNC and DCN in the DR21 filament