Bengaluru scientists decode solar eruptions using Aditya-L1 and Proba-3 satellites

In a first, scientists from Bengaluru and their international collaborators have analysed scientific observations of solar eruptions and studied the coronal mass ejections (CMEs) by using data derived from India’s Aditya-L1 mission and Europe’s Proba-3.

Scientists at the Indian Institute of Astrophysics (IIA) combined observations from the Visible Emission Line Coronagraph (VELC) payload onboard Aditya-L1, and the Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun (ASPIICS) payload onboard Proba-3 to study the mass, density, and energetics of these CMEs in the region very close to the Sun.

The coronagraph onboard Aditya-L1 (VELC) and Proba-3 (ASPIICS) conducted joint observations of almost the same part of the solar corona in two different types of observations (spectroscopic from VELC and imaging from ASPIICS).

ISRO stated that these joint observations provide deeper insights into CME evolution than observations from a single spacecraft.

Sharp images, accurate estimates

“ASPIICS white-light and green coronal emission line observations provide sharp images that enable accurate estimates of a CME’s shape, dynamics, and mass. VELC spectroscopic observations in the green coronal emission line provide information on CME gas at about two million degrees. This gives independent estimates of the CME’s density and thermal energy. The two instruments share a common field of view in the low corona. The team found that only two CMEs, on September 14 and 16, were recorded simultaneously by VELC and ASPIICS from July to December 2025. In both cases, VELC caught the eruptions at an early stage, demonstrating how the two instruments complement each other,” ISRO stated.

According to ISRO, the two CMEs showed two behaviours. The September 14 CME was fast (about 645 km/s) while the September 16 CME was much slower (145 km/s).

“The density of the September 16 CME dropped more steeply with height than that of another CME, indicating its stronger early expansion,” it stated.

The estimates of mass and thermal energy from ASPIICS and VELC agree well, despite the two instruments using different geometric assumptions, physical considerations, and observation types.

Complete, cross-checked view

“In the September 14 CME, thermal energy was only about 1% of the total. In the September 16 CME, thermal energy grew until it matched kinetic energy. The estimated magnetic energy is comparable to, or greater than, the kinetic energy. The results demonstrate the scientific potential of synergetic ASPIICS and VELC observations to constrain the CME mass, density, and energetics in the inner corona, thereby providing new observational constraints on the early evolution of CMEs. The study shows that pairing a coronagraph that images the corona with one that measures its spectrum yields a more complete, cross-checked view of the origin and evolution of CMEs,” ISRO stated.

The Aditya-L1, which is India’s first dedicated solar mission, was launched by PSLV-C57 on September 2 2023. The Proba-3, a mission of the European Space Agency (ESA), was launched by PSLV-XL from Sriharikota December 5, 2024. Two spacecraft are about 150 metres apart, and one casts a shadow on the other.