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Trevor P. Erwin

Publications and source records attributed to Trevor P. Erwin.

2 recordsLinked to original sources

The Length of Martian Crater Rays and Their Relation to Lunar Cold Spots

Impact-generated crater rays are well-documented on the Moon, with most appearing as high-albedo streaks extending radially from a crater's center. On Mars, however, crater rays are significantly rarer and discernible only through thermal imaging due to their lower thermal inertia compared to surrounding terrain. This study presents the first comparative analysis between the lengths of Martian and lunar crater rays, including lunar albedo rays and cold spots, which are ray-like thermal anomalies associated with many of the youngest lunar craters. Our findings indicate that both Martian crater rays and lunar cold spots extend significantly farther than lunar albedo rays, with lengths an order of magnitude greater for craters of equivalent diameter. Furthermore, we propose a connection between the formation mechanisms of Martian crater rays and lunar cold spots based on their thermal properties. By integrating thermal rays into existing ejecta models, we refine the understanding of crater-ray formation and suggest that Martian crater rays and lunar cold spots may share a similar formation mechanism via secondary cratering processes. Advancing knowledge of these features has implications for impact dynamics and surface evolution across planetary bodies.

astro-ph.EP

Laboratory Investigation of CO2-Driven Enhancement of Radiolytic H2O2 on Europa and Other Icy Moons

Observations of Europa's leading hemisphere reveal elevated H2O2 in the warmer, low latitude chaos terrains compared to the colder, polar regions. This distribution disagrees with prior laboratory radiolysis studies of pure water ice, which show higher H2O2 yields at colder temperatures. The regions with higher peroxide abundance, Tara and Powys Regiones, also present increased amounts of CO2, possibly sourced from Europa's interior. To investigate whether CO2 influences radiolysis of water ice to boost H2O2 production, we irradiated water ice doped with varying amounts of CO2 with 10 keV electrons at 70 and 100 K. Our results indicate that CO2, even in trace amounts (< 3%), significantly enhances H2O2 yields at temperatures relevant to Europa. We discuss the mechanisms by which CO2 boosts peroxide synthesis and quantify H2O2 creation and destruction cross sections and G-values across different CO2 concentrations. These findings provide a plausible explanation for the perplexing H2O2 distribution on Europa and has implications for understanding peroxide on other icy bodies such as Ganymede and Charon, where it has been detected alongside CO2.

astro-ph.EP