Multiple Paths of Deuterium Fractionation in Protoplanetary Disks
@article{Aikawa2018MultiplePO, title={Multiple Paths of Deuterium Fractionation in Protoplanetary Disks}, author={Yuri Aikawa and Kenji Furuya and Ugo Hincelin and Eric Herbst}, journal={Japan Geoscience Union}, year={2018} }
We investigate deuterium chemistry coupled with the nuclear spin-state chemistry of H$_2$ and H$_3^+$ in protoplanetary disks. Multiple paths of deuterium fractionation are found; exchange reactions with D atoms, such as HCO$^+$ + D, are effective in addition to those with HD. In a disk model with grain sizes appropriate for dark clouds, the freeze-out of molecules is severe in the outer midplane, while the disk surface is shielded from UV radiation. Gaseous molecules, including DCO$^+$, thus…
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References
SHOWING 1-10 OF 101 REFERENCES
Deuterium Fractionation in Protoplanetary Disks
- Physics, Geology
- 1999
We investigate the chemistry of deuterium-bearing molecules in outer regions of protoplanetary disks, where comets may form. We find that molecules formed in the disk have higher D/H ratios (by which…
The chemistry of multiply deuterated molecules in protoplanetary disks : I. the outer disk
- Physics, Geology
- 2007
We present new models of the deuterium chemistry in protoplanetary disks, including, for the first time, multiply deuterated species. We use these models to explore whether observations in…
WATER IN PROTOPLANETARY DISKS: DEUTERATION AND TURBULENT MIXING
- Physics, Geology
- 2013
We investigate water and deuterated water chemistry in turbulent protoplanetary disks. Chemical rate equations are solved with the diffusion term, mimicking turbulent mixing in a vertical direction.…
Evidence for Multiple Pathways to Deuterium Enhancements in Protoplanetary Disks
- Physics, Geology
- 2012
The distributions of deuterated molecules in protoplanetary disks are expected to depend on the molecular formation pathways. We use observations of spatially resolved DCN emission from the disk…
Evidence for DCO+ as a probe of ionization in the warm disk surface
- Physics, Geology
- 2015
In this Letter we model the chemistry of DCO$^{+}$ in protoplanetary disks. We find that the overall distribution of the DCO$^{+}$ abundance is qualitatively similar to that of CO but is dominated by…
Reprocessing of Ices in Turbulent Protoplanetary Disks: Carbon and Nitrogen Chemistry
- Physics, Geology
- 2014
We study the influence of the turbulent transport on ice chemistry in protoplanetary disks, focusing on carbon and nitrogen bearing molecules. Chemical rate equations are solved with the diffusion…
Evolution of Molecular Abundances in Proto-planetary Disks with Accretion Flow
- Physics, Geology
- 1998
We investigate the evolution of molecular abundances in a protoplanetary disk in which matter is accreting toward the central star by solving numerically the reaction equations of molecules as an…
Volatile carbon locking and release in protoplanetary disks. A study of TW Hya and HD 100546
- Physics, Geology
- 2016
The composition of planetary solids and gases is largely rooted in the processing of volatile elements in protoplanetary disks. To shed light on the key processes, we carry out a comparative analysis…
Exclusion of Cosmic Rays in Protoplanetary Disks. II. Chemical Gradients and Observational Signatures
- Physics
- 2014
The chemical properties of protoplanetary disks are especially sensitive to their ionization environment. Sources of molecular gas ionization include cosmic rays, stellar X-rays and short-lived…