Quantifying Morphological Changes and Sediment Transport Pathways on Comet 67P/Churyumov‐Gerasimenko

Abstract

Comets are composed of primitive materials that once existed frozen in the outer realm of the solar system. These remnants of the earliest era of planetary formation were eventually transported to their current reservoirs through planetary migration and/or interactions with other stars and gas clouds (A'Hearn et al., 2012). While these objects have undergone significant processing before entering their current reservoirs (Lisse et al., 2022;Steckloff et al., 2023), they represent some of the least processed materials in the solar system. Jupiter Family Comets (JFCs) are of particular interest for scientific study due to their short orbital periods, and close perihelion passages that permit detailed spacecraft observations. Broadly, as these objects migrated increasingly closer to the Sun, their volatile-rich surfaces began to evolve as various ices exposed at the surface sublimated. This

Measuring Erosional and Depositional Patterns Across Comet 67P's Imhotep Region

“…The data acquired by the Rosetta mission have allowed us to resolve material transport across a cometary surface for the first time. These observations, detailed in multiple previous studies (Barrington et al., 2023; Birch et al., 2019; El‐Maarry et al., 2017; Fornasier et al., 2017; O. Groussin et al., 2015; Keller et al., 2017; Jindal et al., 2022) have shown that, while sediment may broadly migrate northward through time, local processes significantly modify 67P's surface geology over timescales far shorter than a single orbit. How much of 67P's global geology is set by global, seasonally driven processes versus local (<100m scale) processes, and whether the presently observed smooth terrains are terminal deposits for sedimentary particles, therefore, remain poorly constrained.…”

“…The dune‐like crests (hereafter “crests”) that are found within many smooth deposits on 67P (Barrington et al., 2023; Jia et al., 2017; N. Thomas et al., 2015) were also frequently observed to move back‐and‐forth in a random pattern. Such crests do not appear to move in any preferred direction but instead migrate locally while staying broadly within their original locations.…”

“…(2017). The smooth terrains also host the most rapid changes on 67P that Rosetta observed (Barrington et al., 2023; Birch et al., 2019; El‐Maarry et al., 2017; Fornasier et al., 2017; O. Groussin et al., 2015; Jindal et al., 2022), unlike the consolidated material (Pajola et al., 2017) which displayed very few changes, most of which were traced back to outbursts. Understanding the processes driving the evolution of 67P's smooth terrains is, therefore, crucial to understanding 67P's overall geological evolution.…”

“…The large lobe consists of regions of smooth terrains in both the southern and northern parts of the comet and is therefore an opportune place to look for evidence of sediment transport from the south to the north. Most of the observed surface changes in this region took place between 05/2015 and 01/2016 (Barrington et al., 2023; El‐Maarry et al., 2017; O. Groussin et al., 2015; Jindal et al., 2022). To measure the total change in the sediment in these regions, we employ a shape‐from‐shading technique to create Digital Elevation Models (DEMs) for our regions of interest (ROIs) from images obtained before and after changes are observed on the surface (Section 2).…”

“…The large lobe consists of regions of smooth terrains in both the southern and northern parts of the comet and is therefore an opportune place to look for evidence of sediment transport from the south to the north. Most of the observed surface changes in this region took place between 05/ 2015 and 01/2016 (Barrington et al, 2023;El-Maarry et al, 2017;Jindal et al, 2022). To 2017) and boxes highlighting the regions where DEMs were created.…”