Chemo-dynamical deuterium fractionation in the early solar nebula: The origin of water on Earth and in asteroids and comets

Abstract

Formation and evolution of water in the Solar System and the origin of water on Earth constitute one of the most interesting questions in astronomy. The prevailing hypothesis for the origin of water on Earth is by delivery through water-rich small Solar system bodies. In this paper, the isotopic and chemical evolution of water during the early history of the solar nebula, before the onset of planetesimal formation, is studied. A gas-grain chemical model that includes multiply-deuterated species and nuclear spin-states is combined with a steady-state solar nebula model. To calculate initial abundances, we simulated 1 Myr of evolution of a cold and dark TMC1-like prestellar core. Two time-dependent chemical models of the solar nebula are calculated over 1 Myr: (1) a laminar model and (2) a model with 2D turbulent mixing. We find that the radial outward increase of the H2O D/H ratio is shallower in the chemo-dynamical nebular model compared to the laminar model. This is related to more efficient de-fractionation of HDO via rapid gas-phase processes, as the 2D mixing model allows the water ice to be transported either inward and thermally evaporated or upward and photodesorbed. The laminar model shows the Earth water D/H ratio at r ~<2.5 AU, while for the 2D chemo-dynamical model this zone is larger, r ~<9 AU. Similarly, the water D/H ratios representative of the Oort-family comets, ~2.5-10 x 10-4, are achieved within ~2-6 AU and ~2-20 AU in the laminar and the 2D model, respectively. We find that with regards to the water isotopic composition and the origin of the comets, the mixing model seems to be favored over the laminar model.

28 pages, 5 figures, 2 tables (accepted for publication by ApJ)

References in corpus (12)

• The origins and concentrations of water, carbon, nitrogen and noble gases on Earth
• Spectro-astrometric imaging of molecular gas within protoplanetary disk gaps
• The importance of the ortho:para H2 ratio for the deuteration of molecules during pre-protostellar collapse
• The Scattered Disk as the source of the Jupiter Family comets
• Resolving the chemistry in the disk of TW Hydrae I. Deuterated species
• Chemistry in Protoplanetary Disks: A Sensitivity Analysis
• Water in Protoplanetary Disks: Deuteration and Turbulent Mixing
• The 16OH/18OH and OD/OH isotope ratios in comet C/2002 T7 (LINEAR)
• Warm water deuterium fractionation in IRAS 16293-2422 - The high-resolution ALMA and SMA view
• Turbulence driven diffusion in protoplanetary disks - chemical effects in the outer disk
• A Spitzer Study of Comets 2P/Encke, 67P/Churyumov-Gerasimenko, and C/2001 HT50 (LINEAR-NEAT)
• Water in Comet 2/2003 K4 (LINEAR) with Spitzer

Cited by in corpus (38)

• The ancient heritage of water ice in the solar system
• Origin of water in the inner Solar System: Planetesimals scattered inward during Jupiter and Saturn's rapid gas accretion
• Probing for Exoplanets Hiding in Dusty Debris Disks: Disk Imaging, Characterization, and Exploration with HST/STIS Multi-Roll Coronagraphy
• Global Simulations of the Inner Regions of Protoplanetary Disks with Comprehensive Disk Microphysics
• Water in star-forming regions (WISH): Physics and chemistry from clouds to disks as probed by Herschel spectroscopy
• Multilayer formation and evaporation of deuterated ices in prestellar and protostellar cores
• Water vapor distribution in protoplanetary disks
• Exclusion of Cosmic Rays in Protoplanetary Disks. II. Chemical Gradients and Observational Signatures
• Benchmarking spin-state chemistry in starless core models
• Water deuteration and ortho-to-para nuclear spin ratio of H2 in molecular clouds formed via the accumulation of HI gas
• Chemistry in Disks. IX. Observations and modeling of HCO+ and DCO+ in DM Tau
• Water delivery from cores to disks: deuteration as a probe of the prestellar inheritance of H2O
• Chemical evolution in the early phases of massive star formation II: Deuteration
• Volatile species in comet 67P/Churyumov-Gerasimenko -- investigating the link from the ISM to the terrestrial planets
• The chemistry of disks around T Tauri and Herbig Ae/Be stars
• A Surface Density Perturbation in the TW Hydrae Disk at 95 au Traced by Molecular Emission
• The composition of the protosolar disk and the formation conditions for comets
• Exploring the Origins of Deuterium Enrichments in Solar Nebular Organics
• High D${}_2$O/HDO ratio in the inner regions of the low-mass protostar NGC1333 IRAS2A
• Water in Low-Mass Star-Forming Regions with Herschel: The Link Between Water Gas and Ice in Protostellar Envelopes
• Photodesorption of H2O, HDO, and D2O ice and its impact on fractionation
• Multiple paths of deuterium fractionation in protoplanetary disks
• On water delivery in the inner solar nebula: Monte Carlo simulations of forsterite hydration
• Thermal H/D exchange in polar ice - deuteron scrambling in space
• Detection of water vapor in the terrestrial planet forming region of a transition disk
• Moderate D/H Ratios in Methane Ice on Eris and Makemake as Evidence of Hydrothermal or Metamorphic Processes in Their Interiors: Geochemical Analysis
• Astro & cosmo-chemical consequences of accretion bursts I: the D/H ratio of water
• The chemical structure of the Class 0 protostellar envelope NGC 1333 IRAS 4A
• A D/H Ratio Consistent with Earth's Water in Halley-type Comet 12P from ALMA HDO Mapping
• Machine learning-accelerated chemistry modeling of protoplanetary disks
• Insights into planet formation from debris disks: I. The solar system as an archetype for planetesimal evolution
• Dust Transport in Protoplanetary Disks with Wind-driven Accretion
• Using HCO${}^{+}$ isotopologues as tracers of gas depletion in protoplanetary disk gaps
• Deuterated water ice on the satellites of Saturn
• The HIFI spectral survey of AFGL 2591 (CHESS). III. Chemical structure of the protostellar envelope
• X-ray induced deuterium enrichment on N-rich organics in protoplanetary disks: an experimental investigation using synchrotron light
• Radial variations in nitrogen, carbon, and hydrogen fractionation in the PDS 70 planet-hosting disk
• Deuterated water and the formation of the satellites of Uranus