Automated detection of surface changes on comet 67P

Abstract

The ejection of cometary material is driven by the sublimation of volatiles, and depends on heliocentric distance, local illumination conditions, and material properties. A short period comet like 67P loses 0.1% of its mass per orbit [1], which would amount to 50 cm thick layer of material, if the loss was uniformly spread across the surface. ESA's Rosetta mission followed comet 67P for more than 2 years, monitoring the surface and its evolution through different seasons and heliocentric distances (4-1.2 AU). One of Rosetta's major discoveries was that a significant amount of material is being displaced rather than expelled [2]. Dust is transported from one region to another, or reorganized in place, leading to a local dust cover which appears to expand and contract with seasons. Sporadic events, sometimes linked to outbursts, create more drastic transformations of the surface: e.g. cliff collapses, sudden formation of deep pits, or rapid expansion of surface depressions.

The Ice Composition Close to the Surface of Comet 67P/Churyumov-Gerasimenko

“…In sections and , we compare our results with independent observations, which directly image the surface using optical and spectroscopic measurements. , The detection and analysis of small surface areas based on OSIRIS images has been limited to specific regions and observation windows . An automated approach to map surface deformations and changes seen by optical instruments across the entire nucleus will improve this comparative approach in the future …”

“…16 An automated approach to map surface deformations and changes seen by optical instruments across the entire nucleus will improve this comparative approach in the future. 28 Section 4 introduces a minimal thermophysical model. The nucleus material close to the surface consists of a mixture of various icy components available for sublimation processes and nonvolatile dust grains, partly lifted up by the stream of gas.…”

Determination of the ice composition near the surface of comet 67P/Churyumov-Gerasimenko

“…16 An automated approach to map surface deformations and changes seen by optical instruments across the entire nucleus will improve this comparative approach in the future. 28 Section 4 introduces a minimal thermophysical model. The nucleus material close to the surface consists of a mixture of various icy components available for sublimation processes and non-volatile dust grains, partly lifted up by the stream of gas.…”