Kaboom: Surface Manifestations of Cometary Outbursts

Comets are among the most primitive objects in the solar system, acting as time capsules that preserve clues about the solar system’s origins and early evolution. These icy bodies store volatile compounds that are sporadically released, offering a window into their internal structure and composition. Among the mechanisms of volatile release, outbursts stand out as the most extreme and energetic, marked by sudden brightness increases and the ejection of vast amounts of material into space (Lin et al., 2009; Lin et al., 2017; Vincent et al., 2016). Such explosive events have been observed on a range of cometary bodies—including Jupiter-family comets (Li et al., 2011), centaurs (Donaldson, A., & Scholz, A. 2020), and dynamically new comets (Combi et al. 2019)—and occur under diverse conditions: at perihelion and aphelion, and during midday and/or local night(Rousselot, 2008; Vincent et al., 2016).

     Despite their dramatic nature and scientific importance, the mechanisms driving outbursts and their effects on a comet’s surface morphology remain poorly understood. ESA’s Rosetta mission provided over two years of unprecedented observations of Comet 67P/Churyumov–Gerasimenko (67P), capturing dozens of outbursts throughout the comet’s perihelion passage (Vincent et al., 2016). However, studying the impact of these outbursts on 67P’s surface presents unique challenges due to the comet’s complex bilobate shape, which complicates observation and analyses. This challenge is highlighted by the fact that while 34 major outbursts near perihelion were identified (Vincent et al., 2016), only 6 outburst-associated surface changes were documented prior to this study (Pajola et al., 2017; Fornasier et al. 2017; El-Maarry et al., 2019; Hasselmann et al., 2019). 

     To bridge this gap, we have developed a new tool–the Rosetta Search and Characterization Tool (RoSCo) that allows selecting a region of interest on a 3D shape model of 67P and retrieval of all associated images, followed by precise projection of all images into any user-defined coordinate system. Using RoSCo, we are mapping outburst-driven changes in high-resolution detail and will present a comprehensive analysis of how these energetic events reshape cometary terrain. The results demonstrate that cliff collapses, pit formation, and smooth terrain loss are all capable of sourcing such events. These cascading surface transformations offer critical constraints for refining models of cometary dynamics, volatile redistribution, and long-term landscape evolution. In this presentation, we will present all of our new findings and what our ongoing work will be to fully characterize these most dramatic of comet-shaping events.