Evolution of pits at the surface of 67P/Churyumov-Gerasimenko
arXiv:2210.14634 · doi:10.1051/0004-6361/202243983
Abstract
The observation of pits at the surface of comets offers the opportunity to take a glimpse into the properties and the mechanisms that shape a nucleus through cometary activity. If the origin of these pits is still a matter of debate, multiple studies have recently suggested that known phase transitions alone could not have carved these morphological features on the surface of 67P/C-G. We want to understand how the progressive modification of 67P's surface due to cometary activity might have affected the characteristics of pits. In particular, we aim to understand whether signatures of the formation mechanism of these morphological features can still be identified. To quantify the amount of erosion sustained at the surface of 67P since it arrived on its currently observed orbit, we selected 380 facets of a medium-resolution shape model of the nucleus, sampling 30 pits across the surface. We computed the surface energy balance with a high temporal resolution, including shadowing and self-heating. We then applied a thermal evolution model to assess the amount of erosion sustained after ten orbital revolutions under current illumination conditions. We find that the maximum erosion sustained after ten orbital revolutions is on the order of 80 m, for facets located in the southern hemisphere. We thus confirm that progressive erosion cannot form pits and alcoves, as local erosion is much lower than their observed depth and diameter. We find that plateaus tend to erode more than bottoms, especially for the deepest depressions, and that some differential erosion can affect their morphology. As a general rule, our results suggest that sharp morphological features tend to be erased by progressive erosion. This study supports the assumption that deep circular pits, such as Seth1, are the least processed morphological features at the surface of 67P, or the best preserved since their formation.
References in corpus (17)
- The Active Centaurs
- Origin and Evolution of Short-Period Comets
- Seasonal Mass Transfer on the Nucleus of Comet 67P/Chuyumov-Gerasimenko
- Thermophysical evolution of planetesimals in the Primordial Disk
- A Comet Active Beyond the Crystallization Zone
- Prediscovery Observations and Orbit of Comet C/2017 K2 (PANSTARRS)
- The recent dynamical history of comet 67P/Churyumov-Gerasimenko
- Constraints on cometary surface evolution derived from a statistical analysis of 67P's topography
- Airfall on Comet 67P/Churyumov-Gerasimenko
- C/2010 U3 (Boattini): A Bizarre Comet Active at Record Heliocentric Distance
- Discovery of Carbon Monoxide in Distant Comet C/2017 K2 (PANSTARRS)
- Modelling the water and carbon dioxide production rates of Comet 67P/Churyumov-Gerasimenko
- Thermal processing of Jupiter Family Comets during their chaotic orbital evolution
- P/2019 LD2 (ATLAS): An Active Centaur in Imminent Transition to the Jupiter Family
- The active centaur 2020 MK4
- Ancient and present surface evolution processes in the Ash regionof comet 67P/Churyumov-Gerasimenko
- Small lobe of comet 67P: Characterization of the Wosret region with ROSETTA-OSIRIS