Formation of D2-water and D2-carbonic acid in oxygen-rich solar system ices via D+2 irradiation

Abstract

Molecular oxygen (O2) and carbon dioxide (CO2) ices were irradiated with energetic D+2 ions to simulate the exposure of oxygen-bearing solar system ices to magnetospheric H+2 and H+ ions and energetic protons from the solar wind. The experiments provided evidence on the incorporation of the implanted deuterium and inherent formation of D2-water (D2O) as well as D2-carbonic acid (D2CO3). In the molecular oxygen ices, the temporal profiles inferred that D2-water formation followed successive deuterium atom addition to atomic oxygen via a D-hydroxyl radical intermediate in the matrix. In the carbon dioxide ices, D 2-carbonic acid was likely formed via successive deuterium atom reaction with cyclic carbon trioxide. These chemical processes have specific relevance to water formation on outer solar system bodies, such as the icy moons of Jupiter and Saturn, as well as possible implications for the formation of water on the lunar surface. © 2011. The American Astronomical Society. All rights reserved.