For the first time, scientific observations of the same solar eruptions by India’s Aditya-L1 mission and Europe’s Proba-3 have been jointly analysed to provide deeper insights into the evolution of coronal mass ejections (CMEs) and their impact on Earth than is possible from observations by a single spacecraft.
CMEs are large eruptions from the Sun in which huge amounts of magnetised plasma are thrown out into interplanetary space. When such eruptions are directed towards Earth, they can disturb the near-Earth space environment, trigger geomagnetic storms, disrupt satellite operations and interfere with navigation and communication systems. Measurements of CME parameters near the Sun are very valuable for understanding the physical processes that shape CME properties and subsequent evolution.
However, observing CMEs very close to the solar disk is challenging, and earlier space coronagraphs only partially succeeded in observing them and could not track the early evolution of faint CMEs. As a result, how CME energy is shared between kinetic, thermal and magnetic in the inner corona has remained poorly constrained.
Combining Aditya-L1’s Visible Emission Line Coronagraph (VELC) and Proba-3’s ASPIICS coronagraph shows potential for a better understanding of it, according to information shared by the Indian Space Research Organisation (ISRO) on Friday.
Aditya-L1 is India’s first dedicated solar mission that was launched in September 2023. The spacecraft was successfully placed in a halo orbit around the Sun—Earth and this vantage point facilitates uninterrupted observation of various solar phenomena.
Proba-3 was launched by the European Space Agency (ESA), by IRSO’s PSLV-XL from Sriharikota in December 2024 and it is the world’s first precision formation-flying mission. Two spacecraft fly about 150 meters apart, and one casts a shadow on the other. This creates an artificial solar eclipse in space, allowing the ASPIICS coronagraph to image the corona in optimum conditions.
The two spacecraft measured the mass, density, and energetics of CMEs in the region very close to the Sun. the study was led by researchers from the Indian Institute of Astrophysics along with other European and American solar physicists.
“Our results demonstrate the scientific potential of synergetic ASPIICS and VELC observations for constraining the CME mass, density and energetics in the inner corona, providing new observational constraints on the early evolution of CMEs in a region that has remained difficult to probe with earlier instrumentation,” the researchers said.
The findings have been published in Astronomy and Astrophysics, a peer reviewed journal.
Despite relying on different observational constraints and correspondingly different geometric assumptions, the ASPIICS and VELC derived mass and thermal energy estimates show good mutual agreement. “This consistency lends confidence to the coordinated observation approach as a reliable, cross-validated route to constraining CME properties in the inner corona,” the researchers said.
