View of the 67P comet from the Rosette spacecraft
Scientists have found that molecular oxygen around comet 67P does not form on its surface, but can be produced by the body. The Rosette spacecraft from ESA accompanied the 67P / Churyumov-Gerasimenko comet during its journey to the Sun from August 2014 to September 2016. As a result, managed to put on the surface of the probe.
When the comet approaches the Sun, then the ice on the surface “sublimates” - it turns from a solid state into a gas atmosphere (coma). An analysis of the coma with Rosetta instruments showed the presence of not only water, carbon monoxide and carbon dioxide, but also molecular oxygen.
Molecular oxygen consists of two oxygen atoms joined together. On Earth, it is necessary for the formation of life and is formed during photosynthesis. Previously, he was able to fix around some of Jupiter’s icy moons, but he was not expected to be found around a comet. The Rosetta research team initially reported that oxygen comes from the main body. This would indicate that the comet itself appeared 4.6 billion years ago. But other researchers have suggested that there may be another source. They managed to bring a new way of obtaining molecular oxygen in space, caused by energetic ions - electrically charged molecules. The thought arose that reactions with energy ions on the surface of the comet 67P could become a source.
View of the comet form from Rosette
Rosetta's team recently analyzed 67P oxygen data in light of the emergence of a new theory. They believe that the proposed mechanism of oxygen production on the surface of the comet is insufficient to explain the observed levels in coma.
The theory was tested by observing energetic ions. The amount is simply not enough to form the observed amount of molecular oxygen in a coma. They do not deny that surface generation can occur, but it does not play a major role. Most likely, molecular oxygen was originally located on a comet.