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\t\t\t\t\t\t01\/09\/2025<\/span> The European Space Agency-led Solar Orbiter mission has split the flood of energetic particles flung out into space from the Sun into two groups, tracing each back to a different kind of outburst from our star.<\/p>\n<\/div>\n The Sun is the most energetic particle accelerator in the Solar System. It whips up electrons to nearly the speed of light and flings them out into space, flooding the Solar System with so-called \u2018Solar Energetic Electrons\u2019 (SEEs).<\/p>\n Researchers have now used Solar Orbiter to pinpoint the source of these energetic electrons and trace what we see out in space back to what\u2019s actually happening on the Sun. They find two kinds of SEE with clearly distinct stories: one connected to intense solar flares (explosions from smaller patches of the Sun\u2019s surface), and one to larger eruptions of hot gas from the Sun\u2019s atmosphere (known as \u2018coronal mass ejections\u2019, or CMEs).<\/p>\n<\/p><\/div>\n \u201cWe see a clear split between \u2018impulsive\u2019 particle events, where these energetic electrons speed off the Sun\u2019s surface in bursts via solar flares, and \u2018gradual\u2019 ones associated with more extended CMEs, which release a broader swell of particles over longer periods of time,\u201d says lead author Alexander Warmuth of the Leibniz Institute for Astrophysics Potsdam (AIP), Germany.<\/p>\n While scientists were aware that two types of SEE event existed, Solar Orbiter was able to measure a large number of events, and look far closer to the Sun than other missions had, to reveal how they form and leave the surface of our star.<\/p>\n<\/p><\/div>\n \u201cWe were only able to identify and understand these two groups by observing hundreds of events at different distances from the Sun with multiple instruments \u2013 something that only Solar Orbiter can do,\u201d adds Alexander. \u201cBy going so close to our star, we could measure the particles in a \u2018pristine\u2019 early state and thus accurately determine the time and place they started at the Sun.\u201d<\/p>\n The study is the most comprehensive of SEE events to date, and produces a catalogue that will only grow through Solar Orbiter\u2019s lifetime. It used eight of Solar Orbiter\u2019s ten instruments to observe more than 300 events between November 2020 and December 2022.<\/p>\n \u201cIt\u2019s the first time we\u2019ve clearly seen this connection between energetic electrons in space and their source events taking place at the Sun,\u201d adds co-author Frederic Schuller, also of AIP.<\/p>\n \u201cWe measured the particles in situ \u2013 that is, Solar Orbiter actually flew through the electron streams \u2013 using the probe\u2019s Energetic Particle Detector, while simultaneously using more of the spacecraft\u2019s instruments to observe what was happening at the Sun. We also gathered information about the space environment between the Sun and spacecraft.\u201d<\/p>\n<\/p><\/div>\n The researchers detected the SEE events at different distances from the Sun. This let them study how the electrons behave as they travel through the Solar System, answering a lingering question about these energetic particles.<\/p>\n When we spot a flare or a CME, there\u2019s often an apparent lag between what we see taking place at the Sun, and the release of energetic electrons into space. In extreme cases, the particles seem to take hours to escape. Why?<\/p>\n<\/p><\/div>\n \u201cIt turns out that this is at least partly related to how the electrons travel through space \u2013 it could be a lag in release, but also a lag in detection,\u201d says co-author and ESA Research Fellow Laura Rodr\u00edguez-Garc\u00eda. \u201cThe electrons encounter turbulence, get scattered in different directions, and so on, so we don\u2019t spot them immediately. These effects build up as you move further from the Sun.\u201d<\/p>\n The space between the Sun and the planets of the Solar System isn\u2019t empty. A wind of charged particles streams out from the Sun constantly, dragging the Sun\u2019s magnetic field with it. It fills space and influences how the energetic electrons travel; rather than being able to go where they like, they are confined, scattered, and disturbed by this wind and its magnetism.<\/p>\n<\/p><\/div>\n The study fulfils an important goal of Solar Orbiter: to continuously monitor our star and its surroundings to trace ejected particles back to their sources at the Sun.<\/p>\n \u201cThanks to Solar Orbiter, we\u2019re getting to know our star better than ever,\u201d says Daniel M\u00fcller, ESA Project Scientist for Solar Orbiter. \u201cDuring its first five years in space, Solar Orbiter has observed a wealth of Solar Energetic Electron events. As a result, we\u2019ve been able to perform detailed analyses and assemble a unique database for the worldwide community to explore.\u201d<\/p>\n<\/p><\/div>\n Crucially, the finding is important for our understanding of space weather, where accurate forecasting is essential to keep our spacecraft operational and safe. One of the two kinds of SEE events is more important for space weather: that connected to CMEs, which tend to hold more high-energy particles and so threaten far more damage. Because of this, being able to distinguish between the two types of energetic electrons is hugely relevant for our forecasting.<\/p>\n \u201cKnowledge such as this from Solar Orbiter will help protect other spacecraft in the future, by letting us better understand the energetic particles from the Sun that threaten our astronauts and satellites,\u201d adds Daniel. \u201cThe research is a really great example of the power of collaboration \u2013 it was only possible due to the combined expertise and teamwork of European scientists, instrument teams from across ESA Member States, and colleagues from the US.\u201d<\/p>\n<\/p><\/div>\n Looking ahead, ESA’s Vigil mission will pioneer a revolutionary approach, operationally observing the ‘side’ of the Sun for the first time, unlocking continuous insights into solar activity. To be launched in 2031, Vigil will detect potentially hazardous solar events before they come into view as seen from Earth, giving us advance knowledge of their speed, direction and chance of impact.<\/p>\n Our understanding of how our planet responds to solar storms will also be investigated further with the launch of ESA\u2019s Smile mission next year. Smile will study how Earth endures the relentless \u2018wind\u2019, and sporadic bursts, of fierce particles thrown our way from the Sun, exploring how the particles interact with our planet’s protective magnetic field.<\/p>\n<\/p><\/div>\n Solar Orbiter is a space mission of international collaboration between ESA and NASA, operated by ESA.<\/i><\/p>\n \u00a0<\/p>\n \u00a0<\/p>\n Notes for editors<\/b><\/p>\n \u2018CoSEE-Cat: a Comprehensive Solar Energetic Electron event Catalogue obtained from combined in-situ and remote-sensing observations from Solar Orbiter<\/i>\u2019 by A. Warmuth et al. is published today in\u00a0Astronomy & Astrophysics. <\/i>The results are compiled in a publicly accessible online event catalogue, the Comprehensive Solar Energetic Electron event Catalogue (CoSEE-Cat): https:\/\/coseecat.aip.de\/<\/p>\n More information on the capabilities and leading institutions for each of the instruments used in this study \u2013 EPD, STIX, EUI, RPW, Metis, SoloHI, SWA, and MAG \u2013 is available here: <\/i>https:\/\/www.esa.int\/ESA_Multimedia\/Images\/2020\/01\/Solar_Orbiter_s_instruments<\/p>\n More about Solar Orbiter: https:\/\/www.esa.int\/Science_Exploration\/Space_Science\/Solar_Orbiter<\/p>\n More about Vigil: https:\/\/www.esa.int\/Space_Safety\/Vigil<\/p>\n More about Smile: https:\/\/www.esa.int\/Science_Exploration\/Space_Science\/Smile<\/p>\n Visit ESA\u2019s Space Weather Service Network: or read more about ESA\u2019s space weather activities: https:\/\/www.esa.int\/Space_Safety\/Space_weather<\/p>\n \u00a0<\/b><\/p>\n For more information, please contact <\/b><\/p>\n ESA Media Relations, media@esa.int<\/p>\n<\/p><\/div>\n
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\n\t\t\t\t\t\t\t\t\t\t42<\/span> likes<\/small><\/span><\/p>\n<\/header>\nA clearer connection<\/h3>\n
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\n\t\t\t\t\t\t\t\t<\/figcaption><\/figure>\nFlight delays<\/h3>\n
Keeping Earth safe<\/h2>\n