Constraints on cometary surface evolution derived from a statistical analysis of 67P's topography
Abstract
We present a statistical analysis of the distribution of large scale topographic features on comet 67P/Churyumov-Gerasimenko. We observe that the cumulative cliff height distribution across the surface follows a power law with a slope equal to -1.69 +- 0.02. When this distribution is studied independently for each region, we find a good correlation between the slope of the power law and the orbital erosion rate of the surface. For instance, the northern hemisphere topography is dominated by structures on the 100~m scale while the southern hemisphere topography, illuminated at perihelion, is dominated by 10~m scale terrain features. Our study suggest that the current size of a cliff is controlled not only by material cohesion but by the dominant erosional process in each region. This observation can be generalized to other comets, where we argue that primitive nuclei are characterized by the presence of large cliffs with a cumulative height power index equal to or above -1.5, while older, eroded cometary surfaces have a power index equal to or below -2.3. In effect, our model shows that a measure of the topography provides a quantitative assessment of a comet's erosional history, i.e. its evolutionary age.
Cite
@article{arxiv.1707.00734,
title = {Constraints on cometary surface evolution derived from a statistical analysis of 67P's topography},
author = {J. -B. Vincent and S. F. Hviid and S. Mottola and E. Kuehrt and F. Preusker and F. Scholten and H. U. Keller and N. Oklay and D. de Niem and B. Davidsson and M. Fulle and M. Pajola and M. Hofmann and X. Hu and H. Rickman and Z. -Y. Lin and C. Feller and A. Gicquel and S. Boudreault and H. Sierks and C. Barbieri and P. L. Lamy and R. Rodrigo and D. Koschny and M. F. A'Hearn and M. A. Barucci and J. -L. Bertaux and I. Bertini and G. Cremonese and V. Da Deppo and S. Debei and M. De Cecco and J. Deller and S. Fornasier and O. Groussin and P. J. Gutiérrez and P. Gutiérrez-Marquez and C. Güttler and W. -H. Ip and L. Jorda and J. Knollenberg and G. Kovacs and J. -R. Kramm and M. Küppers and L. M. Lara and M. Lazzarin and J. J. Lopez Moreno and F. Marzari and G. Naletto and L. Penasa and X. Shi and N. Thomas and I. Toth and C. Tubiana},
journal= {arXiv preprint arXiv:1707.00734},
year = {2017}
}