The D/H ratio of water ice in star formation
Abstract
We present the modeling results of deuterium fractionation of water ice in the physical conditions associated with the star formation process such as in the early stages of core condensation and collapse and in the cold mid-plane or warm atmospheres of protoplanetary disks. The interplay between temperature dependent deuterium fractionation and grain surface processes affects the overall deuterium chemistry and on the major deuterium bearing ions and neutrals. We calculated the deuterium chemistry based on reaction rates newly driven using the ortho-para ratios of H2, H3+, H2D+, D2H+, and D3+ (Hugo et al. 2009, J. Chem. Phys., 130, 164302). We adopt equilibrium ortho-para ratios of these species at given gas temperatures. According to our calculations, inclusion of water ice formation alters the deuterium chemistry significantly since deuterium atoms are frozen on cold grain surfaces forming deuterated water ice.
- Publication:
-
The Molecular Universe
- Pub Date:
- May 2011
- Bibcode:
- 2011IAUS..280E...5L