Physics of Lithosphere Seminar

Planetary analogues are crucial for studying space bodies, providing controlled environments to investigate processes, properties, and phenomena that occur on planetary surfaces and interiors. For comets, models are constructed using porous dust-ice agglomerates to replicate the primary components of cometary material, enabling investigations into sublimation pathways, cavity formation, and the behavior of gas and dust under varying conditions. This study presents the results of imaging a scaled-down cometary nucleus model using computed tomography (CT) to examine its internal structure. The CT scanning process generated a three-dimensional representation of the nucleus, with a two-dimensional map of the X-ray attenuation coefficient distribution. Multiple attenuation measurements, processed through reconstruction algorithms, resulted in 248 virtual cross-sections, each 1.25 mm thick. Analysis of these cross-sections revealed cavities where sublimating gas accumulated and veins that facilitated sublimation, reflecting the complex heterogeneity observed in real cometary nuclei. By measuring the volume fractions of the model components, the density of the comet nucleus was determined, aligning with the upper range of densities observed in some comets. These findings highlight the value of laboratory-based cometary models in improving the understanding of the physical processes driving cometary activity and evolution.