The Proba-3 mission, from Agência Espacial Europeia (ESA), made an unprecedented observation by capturing a rare sequence of three solar prominence eruptions. The phenomenon occurred during an observation window of just five hours on September 21, 2025, providing valuable data on the dynamics of Sol’s atmosphere.
The images, taken by the ASPIICS coronagraph, were compiled into a time-lapse animation that reveals gigantic plasma structures being expelled from the solar edge. The data, collected every five minutes, was combined with images of the Sol disk provided by NASA’s Observatório of Dinâmica Solar, offering a complete and detailed view of the event.
Scientists consider the record a milestone, as the occurrence of multiple large eruptions in such a short period of time is extremely unusual. Analysis of these observations is essential to deepen knowledge about the mechanisms that drive space weather and its potential effects on Terra.
The formation flight technology of the Proba-3
The Proba-3 mission stands out for its innovative approach, using two spacecraft that fly in a precise formation, maintaining a distance of approximately 150 meters from each other. Essa unique configuration allows for the creation of artificial solar eclipses in space. One of the craft, the “Occluder”, blocks intense light coming directly from the sun’s disk, allowing the other, the “Coronograph”, to capture sharp images of the inner corona, a region usually obscured by the star’s brightness.
Maintaining this formation requires millimeter precision, controlled by a complex system of sensors and autonomous thrusters that make constant adjustments to ensure perfect alignment. Desde its launch in December 2024, the Proba-3 mission executed several observation sessions that successfully validated the feasibility and effectiveness of the formation flight technology, opening new frontiers for solar observation and astrophysics.
Details of the captured eruptions
The eruptions recorded on September 21, 2025 manifested themselves as solar prominences, which are immense structures formed by relatively colder plasma, supported by complex magnetic field lines in the solar atmosphere. In the animation released by ESA, these structures appear in yellowish tones, standing out against the dark background of space. Andrei Zhukov, researcher at Observatório Real at The inner corona, where these phenomena occur, can reach temperatures of up to one million degrees Celsius, while the prominences are around 10 thousand degrees. It is this remarkable thermal contrast that makes the plasma structures clearly visible to the coronagraph’s sensors, revealing the complex dance of matter and energy in Sol’s vicinity.
Characteristics of solar prominences
Solar prominences are composed of dense plasma that remains suspended for long periods in the atmosphere of Sol, anchored by powerful magnetic forces. Essas structures can remain stable for days or even weeks, forming gigantic arcs that stretch hundreds of thousands of kilometers.
However, when the delicate magnetic balance that supports them is disturbed, stability is lost. Essa instability results in the abrupt release of material contained in the prominence, which is launched in various directions into interplanetary space.
Some of this expelled plasma can evolve into what is known as a coronal mass ejection (CME), one of the main sources of disturbances in space weather. CMEs travel at very high speeds and, if directed towards Terra, can interact with our planet’s magnetic field.
This interaction can trigger geomagnetic storms, with the potential to affect communications satellites, GPS navigation systems and power distribution networks. Embora the September 2025 eruptions did not send significant material toward Terra, the data collected is crucial to improving prediction models for these events.
Innovation of the ASPIICS instrument
The ASPIICS coronagraph (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Enquanto one spacecraft acts as an external occluder disk, the other houses the main telescope responsible for capturing the images.
This distributed instrument architecture is what makes it possible to observe regions of the corona much closer to Sol than would be possible with traditional coronagraphs, whether ground-based or on a single orbital platform. Alignment accuracy reaches millimeter levels, even with ships 150 meters away.
In addition to images, ASPIICS collects polarimetric data, which reveals crucial information about the density, temperature and direction of movement of the coronal plasma. Esses parameters are essential for unraveling mysteries such as the origin of the solar wind and the acceleration of coronal ejections.
Context of solar cycle 25
The event observed by Proba-3 occurs during a period of high solar activity. Solar cycle 25, which began in 2019, reached its peak of activity between 2024 and 2025, showing a significant increase in the number of sunspots, eruptions and other energetic phenomena. Forecasts indicate that activity levels will remain high throughout 2026.
During this solar maximum, high-energy flares have been recorded more frequently, an increase in the number of coronal mass ejections and a greater incidence of geomagnetic storms of moderate intensity. Essa activity, which exceeded initial projections, reinforces the importance of continuous monitoring to anticipate and mitigate impacts on critical infrastructures in Terra and in space.
Importance of coronal observation
The inner solar corona remains one of the most enigmatic and challenging regions for scientific study. The fact that its temperature increases dramatically as it moves away from the visible surface of Sol, the photosphere, is a puzzle that solar physics has yet to fully solve. Instrumentos like ASPIICS, capable of observing the corona from just 1.1 solar radii from the star’s center, provide crucial data for investigating the energy transfer mechanisms that cause this anomalous heating. Essas observations, previously dependent on rare total solar eclipses, can now be made in a controlled and repeated manner, boosting scientific research.
Applications in space monitoring
Detailed information about the solar corona, such as that obtained by Proba-3, is vital for improving space weather warning systems. Agências around the world use this data to develop more accurate forecasts that help reduce risks to orbiting satellites, ground power grids and human space missions. An early warning allows satellite operators to put their equipment in safe mode and electrical companies to prepare their networks for possible overloads, minimizing damage caused by severe geomagnetic storms.
