What is it about?
The Ca-exosphere of Mercury has been observed by MESSENGER. Here, we test the hyporthesis that this exosphere is generated through the interaction of the meteoroid stream of comet Encke with the planet's surface. This was previously thought possible. Here we have made simulations to confirm the observed morphology of Mercury's Ca-exosphere. Moreover, we simulate the CaO exosphere which has not been observed yet.
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Why is it important?
Our findings can be useful in the planning of the exosphere observations for BepiColombo, the upcoming European Space Agency-Japanese Aerospace Exploration Agency mission to Mercury.
Perspectives
Our knowledge on the details of the Ca-extraction mechanism at Mercury's surface is currently limited. Experiments provide evidence that a significant amount of energetic atomic Ca can be released through the dissociative ionization mechanism upon high-velocity impacts. If this is the case of Mercury, our findings based on simulations would further support the micrometeoroid impact vaporization process being the culprit for producing the observed energetic Ca exosphere and the comet Encke stream particles being the main agent of the exosphere’s seasonal variation. A synergetic multidata analysis of the Hermean neutral environment and of its assumed sources with BepiColombo would provide important feedback on the role of the Encke micrometeoroids in the Ca-exosphere generation.
Dr Christina Plainaki
Agenzia Spaziale Italiana
Read the Original
This page is a summary of: Investigation of the possible effects of comet Encke's meteoroid stream on the Ca exosphere of Mercury, Journal of Geophysical Research Planets, June 2017, Wiley,
DOI: 10.1002/2017je005304.
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