India’s Aditya-L1 and Europe’s Proba-3 Join Forces to Decode Solar Eruptions

India’s Aditya-L1 solar mission and the European Space Agency’s Proba-3 mission have jointly analysed two powerful eruptions from the Sun, giving scientists a more detailed view of how these events develop close to their source. Researchers combined observations from Aditya-L1’s Visible Emission Line Coronagraph (VELC) and Proba-3’s ASPIICS coronagraph to estimate the mass, density and energy of two coronal mass ejections (CMEs). The study, led by scientists at the Indian Institute of Astrophysics (IIA) in Bengaluru with international collaborators, was published in Astronomy & Astrophysics in October 2026.

The research focuses on a difficult stage of solar physics: understanding what happens to an eruption while it is still close to the Sun. CMEs release huge quantities of magnetised plasma into space, and those directed towards Earth can disturb the planet’s space environment. By combining two instruments that observe the solar corona in different ways, scientists were able to cross-check measurements and better constrain how energy is divided between the eruption’s motion, heat and magnetic field. The work strengthens scientific understanding of solar activity, although it does not itself amount to a new operational warning system for solar storms.

Key Takeaways

• First joint analysis: Aditya-L1 and Proba-3 observations of the same solar eruptions have been analysed together in a published study.
• Two events examined: The spacecraft jointly observed CMEs on September 14 and September 16, 2025.
• Different instruments: Aditya-L1’s VELC provides spectroscopic measurements, while Proba-3’s ASPIICS captures images of the solar corona.
• Different energy patterns: Thermal energy was about 1% of the total in one CME; in the other, it grew to become comparable to kinetic energy.
• Magnetic energy matters: Estimated magnetic energy was comparable to or greater than kinetic energy in both events.
• Why it matters: Better measurements close to the Sun can help researchers understand how CMEs evolve and assess their potential effects on Earth.
• India’s contribution: The work highlights Aditya-L1’s growing scientific role and cooperation between Indian, European and American researchers.

What Are Coronal Mass Ejections?

The Sun is not a quiet ball of gas. Its atmosphere contains plasma, electrically charged particles that interact with powerful magnetic fields. These fields can become twisted and stressed as solar activity changes, sometimes releasing large amounts of energy and material into space.

A coronal mass ejection is a large eruption of magnetised plasma from the Sun’s outer atmosphere, known as the corona. A CME can carry billions of tonnes of material and travel through interplanetary space at speeds that vary substantially from event to event.

Not every CME affects Earth. The impact depends on its direction, speed, magnetic structure and interaction with the solar wind and Earth’s magnetic field. When a CME is directed towards Earth and interacts strongly with the magnetosphere, it can contribute to a geomagnetic storm.

Such storms can affect satellite operations, radio communications, navigation systems and other technologies that depend on the near-Earth space environment. Strong events can also induce currents in long power-transmission lines and create operational challenges for electricity networks.

Scientists therefore want to understand not just whether an eruption occurs, but how it forms, how much material it carries, how its magnetic field evolves and how quickly it moves away from the Sun.

Why Studying Solar Eruptions Near the Sun Is Difficult

A CME changes as it travels outward. Its shape expands, its density changes and its energy is distributed among different physical processes. Measurements taken farther from the Sun may not reveal exactly how the eruption began or how its properties developed during its earliest stages.

Observing the inner corona is technically difficult because the Sun’s bright surface overwhelms the much fainter light from its surrounding atmosphere. A coronagraph addresses this problem by blocking the direct light from the solar disc, making it easier to observe material around the Sun.

Even then, no single measurement captures every aspect of a CME. Images can reveal the shape and movement of an eruption, but estimating the temperature and density of the plasma requires additional information. Spectroscopy, which studies the light emitted at specific wavelengths, can provide clues about the physical conditions of the material.

This is where the two missions become complementary. Rather than relying on a single instrument and its assumptions, researchers can compare measurements obtained through different observational methods.

The joint analysis provides a way to check whether independent estimates agree and to refine calculations of the eruption’s physical properties.

How Aditya-L1 and Proba-3 Work Together

India’s Aditya-L1 is the country’s first dedicated space-based solar observatory. Launched on September 2, 2023, it entered a halo orbit around the Sun-Earth L1 point on January 6, 2024. This position, roughly 1.5 million kilometres from Earth towards the Sun, gives the spacecraft a sustained view of solar activity.

Its VELC instrument, developed by the Indian Institute of Astrophysics in collaboration with ISRO, studies the solar corona using imaging and spectroscopic observations. In the joint study, its measurements helped researchers estimate properties of the hot plasma, including density and thermal energy.

Proba-3 is an ESA mission launched on December 5, 2024. It uses two spacecraft flying in precise formation, approximately 150 metres apart, to create an artificial solar eclipse in space. One spacecraft blocks the Sun’s bright disc from the perspective of the other, allowing the ASPIICS coronagraph to observe the faint corona.

The two instruments cover overlapping regions close to the Sun but collect different kinds of information.

Mission and instrument	Main contribution to the study
Aditya-L1 / VELC	Spectroscopic measurements that help estimate plasma density and thermal properties
Proba-3 / ASPIICS	Coronagraph images that help establish CME shape, dynamics and mass
Combined observations	Cross-checks and improved constraints on the eruptions’ physical properties and energy

The value of this collaboration lies in combining complementary observations rather than treating either mission as a replacement for the other. Together, they provide a more complete view of the inner corona.

What the Two Solar Eruptions Revealed

The researchers examined two CMEs recorded by both instruments on September 14 and September 16, 2025. These were the two events observed simultaneously by VELC and ASPIICS during the July-to-December 2025 period identified in the report.

The eruptions behaved differently. The September 14 CME travelled at approximately 645 kilometres per second, while the September 16 event moved at around 145 kilometres per second. The slower eruption also showed a steeper decline in density with height, suggesting stronger early expansion.

The study’s energy estimates revealed another important difference.

In the September 14 event, thermal energy accounted for only about 1% of the total estimated energy. In the September 16 event, thermal energy increased until it became comparable to kinetic energy. In both cases, estimated magnetic energy was comparable to or greater than kinetic energy.

These findings show why it is important not to assume that every CME develops in the same way. Two eruptions can differ in speed, density evolution and the relative importance of heat, motion and magnetic fields.

The results also matter because the energy distribution can provide clues about the physical processes shaping an eruption. Researchers can use such measurements to test models of how CMEs are launched and how they evolve in the inner corona.

Why Cross-Checking Measurements Matters

The study’s value is not limited to the differences between the two eruptions. The researchers also found that the instruments’ independent estimates of mass and thermal energy agreed well, despite their use of different observational methods and assumptions.

That agreement is significant because estimates of a CME’s properties depend on how the observations are interpreted. Researchers must account for factors such as the eruption’s geometry, the amount of material along the line of sight and the physical conditions of the emitting plasma.

When two different methods produce consistent estimates, scientists gain confidence in the measurements. When they disagree, the differences can point to assumptions that need further examination.

The combined approach therefore offers a way to improve the reliability of measurements in a region where direct observations remain challenging.

It does not remove all uncertainty. The study involved two jointly observed CMEs, so its results cannot automatically be applied to every type of solar eruption. More observations across different events will be needed to establish how broadly the findings hold.

How This Research Could Improve Space-Weather Science

Space weather describes changing conditions in the space environment driven largely by solar activity. CMEs are among the events that can produce significant disturbances when their trajectories and magnetic structures bring them into contact with Earth’s magnetosphere.

Understanding an eruption near the Sun is useful because scientists need to know how it begins and how its properties change as it moves outward. Measurements of mass, density, speed and magnetic energy can help researchers refine physical models of CME development.

Better models could eventually contribute to improved estimates of how an eruption may evolve during its journey through space. That knowledge is relevant to forecasting potential effects on satellites, navigation systems, communications and other infrastructure.

However, there is an important distinction between better scientific measurements and an operational forecast. The new study does not claim that the two missions can now predict every geomagnetic storm or determine precisely how a particular CME will affect Earth. Space-weather forecasting also depends on continued observations, modelling and measurements of the solar wind and magnetic field.

The research provides additional observational constraints that can help improve those scientific tools over time.

What the Collaboration Means for India’s Space Programme

Aditya-L1’s contribution demonstrates the scientific value of India’s investment in a dedicated solar observatory. The mission was designed to study the solar corona, solar wind, magnetic fields and other phenomena that influence the Sun-Earth connection.

The VELC instrument’s ability to contribute measurements to a joint international study also illustrates how space science missions can deliver value beyond their individual observations. Combining data across missions allows researchers to investigate questions that would be harder to answer using a single spacecraft.

The collaboration with ESA’s Proba-3 also highlights the international nature of modern solar physics. Solar eruptions cross national boundaries, and understanding them requires observations, specialised instruments and scientific expertise from multiple research groups.

The study was led by researchers at the Indian Institute of Astrophysics, Bengaluru, alongside European and American solar physicists. Its publication in Astronomy & Astrophysics places the work within the international research effort to understand the Sun’s atmosphere and its effects on the space environment.

The Bigger Picture

The joint Aditya-L1 and Proba-3 observations show how combining different instruments can reveal more about the physical processes behind solar eruptions. The two CMEs displayed different energy patterns, while independent measurements of mass and thermal energy agreed well. This provides researchers with useful constraints for studying how CMEs develop close to the Sun, where direct observations remain challenging.

For India, the findings highlight Aditya-L1’s role in international solar research. For space-weather science, the results offer better evidence for testing models of CME evolution, but they should be viewed as a contribution to a larger effort rather than a complete solution to solar-storm forecasting.

Looking Ahead

Further coordinated observations will be important for determining whether the patterns identified in these two eruptions are common across a broader range of CMEs. Scientists can use future measurements to compare eruptions with different speeds, densities and magnetic properties, improving their understanding of how energy is distributed during the earliest stages of an event.

Over time, better measurements and more reliable physical models could strengthen the scientific basis for space-weather forecasting. Aditya-L1 and Proba-3 demonstrate how international missions can work together to address difficult questions about the Sun, while the practical benefits will depend on continued observations and validation across many events.

Frequently Asked Questions

1. What did India’s Aditya-L1 and Europe’s Proba-3 discover?

Researchers jointly analysed two CMEs observed on September 14 and 16, 2025, measuring their mass, density and energy. The study found different energy distributions between the events and agreement between the instruments’ independent mass and thermal-energy estimates.

2. What is a coronal mass ejection?

A CME is a large eruption of magnetised plasma from the Sun’s corona. If it is directed towards Earth, it can disturb the magnetosphere and contribute to geomagnetic storms.

3. What is the role of Aditya-L1’s VELC instrument?

VELC observes the solar corona using imaging and spectroscopy. In this study, its spectroscopic measurements helped researchers estimate the density and thermal properties of the erupting plasma.

4. How does ESA’s Proba-3 observe the solar corona?

Proba-3 uses two spacecraft flying in precise formation to create an artificial eclipse. This blocks the Sun’s bright disc and allows its ASPIICS coronagraph to image the faint surrounding corona.

5. Does the discovery mean solar storms can now be predicted accurately?

No. The study improves understanding of CME properties close to the Sun, but it does not establish a complete operational forecasting system. Predicting Earth impacts requires additional observations and modelling.

6. Where was the research published?

The study, led by researchers from the Indian Institute of Astrophysics and international collaborators, was published in the journal Astronomy & Astrophysics in October 2026.