The joint European-Japanese objective, BepiColombo, has exposed how high-energy auroras on Mercury are formed. The research study indicates that electrons, accelerated in Mercurys magnetosphere and precipitating onto the planets surface, communicate with the surface area product to discharge X-rays and produce the auroras. The BepiColombo objective consists of two spacecraft, the Mercury Planetary Orbiter (MPO) led by ESA, and the Mercury Magnetospheric Orbiter (MMO, dubbed Mio post-launch) supervised by JAXA. Throughout its inaugural Mercury flyby, BepiColombo skimmed 200 kilometers above the worlds surface, with Mios onboard plasma instruments assisting in the first simultaneous observations of different types of charged particles from the solar wind near Mercury.
During the flyby, BepiColombo came near Mercury from the night side of the northern hemisphere and made its closest technique near the morning side of the southern hemisphere.
Artists representation of the ESA/JAXA BepiColombo objective flying through speeding up electrons that can set off X-ray auroras on the surface area of Mercury. Credit: Thibaut Roger/Europlanet
The joint European-Japanese objective, BepiColombo, has revealed how high-energy auroras on Mercury are formed. The research suggests that electrons, sped up in Mercurys magnetosphere and speeding up onto the worlds surface, communicate with the surface product to discharge X-rays and produce the auroras. This discovery highlights the commonality of auroral systems throughout the Solar System.
BepiColombos Mission and Discovery
BepiColombo, the joint European Space Agency (ESA) and Japanese Aerospace Exploration Agency (JAXA) mission, has revealed how electrons drizzling down onto the surface area of Mercury can activate high-energy auroras.
This mission, bound for the inner world of the Solar System because 2018, executed its very first Mercury flyby on October 1, 2021. A worldwide group of scientists analyzed the information collected by three of BepiColombos instruments during this encounter, with the findings released on July 18 in the scientific journal, Nature Communications.
Artist impression of BepiColombo flying by Mercury on October 1, 2021. The spacecraft makes 9 gravity assist maneuvers (one of Earth, 2 of Venus, and six of Mercury) before entering orbit around the innermost planet of the Solar System in 2025. Credit: ESA/ATG medialab
How Mercurys Auroras are Formed
Auroras on Earth are produced by the interaction of the solar wind– a stream of charged particles from the Sun– and our worlds ionosphere, which is electrically charged. Unlike Earth, Mercury has an extremely thin atmosphere understood as an exosphere, triggering its auroras to be formed from the solar winds direct interaction with the planets surface area.
The BepiColombo Spacecraft and Observations
The BepiColombo objective includes two spacecraft, the Mercury Planetary Orbiter (MPO) led by ESA, and the Mercury Magnetospheric Orbiter (MMO, called Mio post-launch) supervised by JAXA. Both are in a docked setup for the seven-year journey to their final orbit. Throughout its inaugural Mercury flyby, BepiColombo skimmed 200 kilometers above the worlds surface area, with Mios onboard plasma instruments facilitating the first synchronised observations of different kinds of charged particles from the solar wind near Mercury.
Findings and Researchers Insight
Sae Aizawa, lead author from the Institut de Recherche en Astrophysique et Planétologie (IRAP), currently connected with JAXAs Institute of Space and Astronautical Science (ISAS) and the University of Pisa, Italy, commented, “For the first time, we have seen how electrons are sped up in Mercurys magnetosphere and precipitated onto the planets surface area. While Mercurys magnetosphere is much smaller than Earths and has a different structure and characteristics, we have verification that the system that generates aurorae is the very same throughout the Solar System.”
BepiColombos Route and Observations
During the flyby, BepiColombo came near Mercury from the night side of the northern hemisphere and made its closest technique near the morning side of the southern hemisphere. The mission observed the magnetosphere on the southern hemispheres daytime side before exiting the magnetosphere back into the solar wind. Its instruments successfully observed the magnetospheres structure and limits, which revealed that the magnetosphere was abnormally compressed, likely due to high-pressure conditions in the solar wind.
Electron Acceleration and Auroras on Mercury
The high-energy electrons are carried from the tail area towards the world, where they lastly drizzle down on Mercurys surface area. While NASAs MESSENGER objective had actually previously observed auroras at Mercury, the processes activating the X-ray fluorescence from the surface had not been well understood or directly observed up until now.
Recommendation: “Direct proof of substorm-related impulsive injections of electrons at Mercury” by Sae Aizawa, Yuki Harada, Nicolas André, Yoshifumi Saito, Stas Barabash, Dominique Delcourt, Jean-André Sauvaud, Alain Barthe, Andréi Fedorov, Emmanuel Penou, Shoichiro Yokota, Wataru Miyake, Moa Persson, Quentin Nénon, Mathias Rojo, Yoshifumi Futaana, Kazushi Asamura, Manabu Shimoyama, Lina Z. Hadid, Dominique Fontaine, Bruno Katra, Markus Fraenz, Norbert Krupp, Shoya Matsuda and Go Murakami, 18 July 2023, Nature Communications.DOI: 10.1038/ s41467-023-39565-4.
The study was brought out by a research group composed of the French Institut de Recherche en Astrophysique et Planétologie (IRAP), Kyoto University, ISAS, the Laboratoire de Physique des Plasmas (France), the Max Planck Institute for Solar System Research (Germany), the Swedish Institute of Space Physics, Osaka University, Kanazawa University, and Tokai University. The work was partly supported through Europlanet 2024 Research Infrastructure funding from the European Commission under grant agreement No 871149.