A Geoscientific Review on CO and CO2 Ices in the Outer Solar System

Abstract

Ground-based telescopes and space exploration have provided outstanding observations of the complexity of icy planetary surfaces. This work presents our review of the varying nature of carbon dioxide (CO2) and carbon monoxide (CO) ices from the cold traps on the Moon to Pluto in the Kuiper Belt. This review is organized into five parts. First, we review the mineral physics (e.g., rheology) relevant to these environments. Next, we review the radiation-induced chemical processes and the current interpretation of spectral signatures. The third section discusses the nature and distribution of CO2 in the giant planetary systems of Jupiter and Saturn, which are much better understood than the satellites of Uranus and Neptune, discussed in the subsequent section. The final sections focus on Pluto in comparison to Triton, having mainly CO, and a brief overview of cometary materials. We find that CO2 ices exist on many of these icy bodies by way of magnetospheric influence, while intermixing into solid ices with CH4 (methane) and N2 (nitrogen) out to Triton and Pluto. Such radiative mechanisms or intermixing can provide a wide diversity of icy surfaces, though we conclude where further experimental research of these ices is still needed.

Ozone production in electron irradiated CO2:O2 ices

“…[63][64][65] CO 2 ices there may also be intermixed with smaller quantities of non-native O 2 ice sourced from the charged particle and ultraviolet photon irradiation of the surface. 66 As such, our experimental results suggest that there should be some O 3 formed at the surfaces of these moons as a result of their interaction with the Uranian magnetosphere.…”

Widespread CO2 and CO in the Trans-Neptunian Population revealed by JWST/DiSCo-TNOs

“…CO ice has been previously reported in Pluto and is believed to be supported by the dwarf-planet's atmosphere via vapor pressure equilibrium and seasonal cycle activity 46,47 these species, when mixed with H 2 O ice, could also form complex organics, which may explain the redder spectral slope of these objects 8,50 . Additionally, a small amount of CO 2 may also have been produced by irradiation, summing up to the original inventory of CO2 in the body .…”

Martian Araneiforms: A Review

“…More examples of dendritic features may be found as more of the solar system is imaged at higher resolution. CO 2 ice is found broadly within the Solar System (described in detail in Ahrens et al (2022)), from localized pockets within cold traps at the lunar poles (Schorghofer et al, 2021) to varying abundances across the Jovian satellites (e.g., G. B. Hansen and McCord, 2008;Hibbitts et al, 2003Hibbitts et al, , 2000McCord et al, 1998).…”

“…CO 2 ice is found broadly within the Solar System (described in detail in Ahrens et al. (2022)), from localized pockets within cold traps at the lunar poles (Schorghofer et al., 2021) to varying abundances across the Jovian satellites (e.g., G. B. Hansen and McCord, 2008; Hibbitts et al., 2003, 2000; McCord et al., 1998). However, sublimation timescales as well as substrate properties vary greatly among the distribution of CO 2 ices within the inner and outer Solar System and erosive substrate is unlikely on icy crusts.…”