Slope lineae as potential indicators of recent volatile loss on Mercury

Slope lineae are enigmatic, bright, and seemingly young features on Mercury. Past investigations hypothesized that lineae occurrence might be tied to volatile loss, analogous to hollows, but no systematic analysis has been conducted. Here, we use a deep learning-driven approach to map 402 slope lineae across the planet. Lineae seem to feature blue spectral slopes and tend to originate from hollows or bright, ‘hollow-like’ features located on the equator-facing walls of young impact craters that penetrated volcanic smooth plains, implying that lineae activity could be driven by heat loss, insolation, and the devolatilization of subsurface phases like sulfur. We do not observe any geomorphic lineae activity between 2011 and 2015, suggesting that activity occurs on timescales longer than ~4 years or below MESSENGER’s spatial resolution. Lineae activity as a geomorphic indicator of recent or ongoing volatile loss on Mercury represents a specific hypothesis that can be scrutinized by ESA/JAXA BepiColombo. A comprehensive mapping approach using MESSENGER data finds that slope lineae on Mercury are preferentially oriented towards the equator on the sun-facing slopes of impact craters, suggesting they form through volatile release due to insolation