Morphometric analysis of Pluto's impact craters

Author(s)

Caio Vidaurre Nassif Villaça

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Geociências
• Defense date: 2021-02-08

Examining board members

Alvaro Penteado Crósta; Débora Correia Rios; Emilson Pereira Leite

• Advisor: Carlos Henrique Grohmann de Carvalho; Alvaro Penteado Crósta

Abstract

Morphometry data of impact craters are fundamental for understanding the evolution of the Solar System and its planetary component bodies. In July 2015, the New Horizons probe imaged approximately 35% of Pluto's surface. Since then, some preliminary studies regarding the morphometry of its impact craters have been carried out, although the subject needs to be further investigated. The scope of this work is to carry out a detailed analysis of the morphometry of Pluto’s impact craters, using images from the New Horizons mission with resolutions varying between 80 and 400 m/px. A global Pluto DEM (Digital Elevation Model) with a resolution of 300 m/px, created from stereoscopic pairs, was used to extract the morphometric data of impact craters. Pluto's surface was divided according to crater morphometric characteristics to analyze possible differences in impact dynamics and erosion rates in each region. Data were obtained regarding the depth of the craters, diameter, inclination of the inner wall, standard deviation of depth, diameter of the base of the crater and thickness of the walls. Based on data analysis we conclude that craters of same diameter above 30ºN are shallower than their equatorial equivalents. This phenomenon may be related to the presence of more volatiles near the north pole. We propose two hypotheses: 1) The presence of volatiles can affect the formation of craters by making the impacted surface weaker and susceptible to major changes (e.g., mass sliding and collapse of the walls) during the crater formation process, until they reach stabilization. 2) The higher concentration of volatiles can affect the depth of the craters by means of atmospheric decantation, considering that these elements have decantation and sublimation cycles that vary according to Pluto’s different seasons. The transition diameter from simple to complex crater was found to change throughout the areas of study. Craters within areas 1 and 4 exhibit a transition diameter (Dt) of approximately 10 km, while Dt for craters within areas 3 and 5 occurs at 15 km, approximately. This difference in Dt in different regions may be related to different proportions between rocky material and ice on the surface of the dwarf planet (AU)

• FAPESP's process: 18/22724-4 - Morphometric analysis of Pluto impact craters
• Grantee: Caio Vidaurre Nassif Villaça
• Support Opportunities: Scholarships in Brazil - Master