A group of scientists who are studying the comet 67P/Churyumov-Gerasimenko has created a map based on the analysis of surface images taken by the OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) instrument of the Rosetta space probe. The result is that the comet can be divided into different regions that have distinct physical appearancec. This map shows that it’s much more than a large rock mixed with ice.
Since the beginning of August, the Rosetta space probe has been studying the comet 67P/Churyumov-Gerasimenko more and more closely sending photos that showed its geological complexity. The discovery of this comet’s very irregular shape had already shown that its choice as the mission objective was really lucky. Now the creation of this detailed map of its surface shows its layering that provides clues about its history.
The surface of the comet 67P/Churyumov-Gerasimenko shows a remarkable variety of geological features. It’s not just the two lobes joined by a neck because the surface is full of craters but also of cliffs, depressions and other irregularities. It’s the first time that the nucleus of a comet is mapped with such precision but this is just the beginning of the task of studying it thats aim to understand its history.
The shape of the comet 67P/Churyumov-Gerasimenko with two lobes joined by a neck raised the issue of figuring out whether there are two nuclei that merged in the past or there’s a single nucleus that got eroded. The answer may be given by analyzing the stratification of the surface: if there’s a continuity of the layers between the two lobes, it’s likely that the comet is composed of a single nucleus.
The comet 67P/Churyumov-Gerasimenko is slowly getting closer to the Sun so a certain activity started with sublimation of the ice, which gets vaporized. In several areas, the surface is falling apart, also with the emission of dust. The observation of this activity will help to understand how the various geological features got formed on the comet’s surface.
This map will also help the members of the Rosetta mission team to choose a landing place for the Philae lander. In the coming days, there will be a meeting in which the five sites that were already selected as candidates will be further analyzed. On Monday, September 15, an announcement is expected for the site selected as the primary target for the landing and a second site selected as a backup.