Pariksha SaathiAditya-L1's VELC shows a solar eruption expanded asymmetrically, not like a simple symmetric bubble: IIA study
Scientists from the Indian Institute of Astrophysics (IIA), an autonomous institution of the Department of Science and Technology (DST), have used data from the Visible Emission Line Coronagraph (VELC) on board Aditya-L1 to show that a solar eruption, or coronal mass ejection (CME), did not expand outward from the Sun like a simple symmetric bubble, as previously thought, but underwent non-uniform expansion and developed an asymmetric shape, the Ministry of Science and Technology said on 3 November 2026; according to the release, the study, published in the Astrophysical Journal Letters, showed this for the first time. The scientists combined VELC data with complementary observations from NASA's Solar Dynamics Observatory (SDO) and three-dimensional modelling to reconstruct the full 3-D geometry and dynamics of the eruption, observing the CME of 5 August 2024, which was launched from an active region near the western limb of the Sun. VELC, the primary payload among Aditya-L1's 7 payloads, is an internally occulted coronagraph that studies nascent CMEs through spectroscopy in the 530.3 nm green emission line of highly ionised iron in the corona, which captures hot coronal plasma at around 1.8 million Kelvin; its data showed blue-shifted and red-shifted emission from plasma moving towards and away from the observer. A model with symmetric expansion could not reproduce this pattern, while a model with an inclined CME axis and asymmetric lateral expansion did. The researchers said such differences in expansion can affect a CME's speed and its arrival time at Earth, which matters for space weather. Aditya-L1, India's first space-based solar observatory, was launched in September 2023 and is operational at the Sun–Earth L1 point; VELC was designed and fabricated by IIA at its MGK Menon Lab for Space Sciences on the CREST campus in Hosakote, with substantial support from ISRO.
Drafted with AI assistance from the official PIB release linked above and checked against it by a second AI pass. Not line-edited by a human.
Learning context
An ISRO article of 10 December 2024 describes VELC's observations of a CME. Aditya-L1, India's first space-based solar mission, was launched on 2 September 2023 and placed on 6 January 2024 in a halo orbit around the first Sun-Earth Lagrange Point L1, about 1.5 million km from the Earth. Researchers from the Indian Institute of Astrophysics used VELC to study a CME observed on 16 July 2024, focusing on the green emission line at 5303 Å produced by iron atoms at very high temperatures in the corona, and reported their results in The Astrophysical Journal Letters. In the affected region the corona's brightness dropped by about 50%, a 'coronal dimming' that lasted about 6 hours; the region's temperature was enhanced by about 30% and it became more turbulent; and Doppler measurements showed the ejected plasma moving away from the observer at about 10 km per second, indicating a deflection of the CME by the Sun's magnetic field. ISRO explains that when a CME reaches Earth it can disrupt satellite communications, GPS systems and power grids.
Check yourself: when was Aditya-L1 placed in its halo orbit around L1, and by about how much did the corona's brightness drop during the CME of 16 July 2024 observed by VELC?
On 6 January 2024; by about 50% (a coronal dimming lasting about 6 hours).
Revision task: from this release, note the institute and department behind the study, the journal, the date of the CME observed, the finding about its shape, VELC's wavelength and the plasma temperature it captures, the number of Aditya-L1's payloads and why the finding matters for space weather; from the note, Aditya-L1's launch and halo-orbit dates, L1's distance from Earth, and the dimming, temperature and Doppler findings on the CME of 16 July 2024.
Test yourself
Data from which payload on board Aditya-L1, combined with observations from NASA's SDO, showed that a coronal mass ejection expanded asymmetrically rather than like a simple symmetric bubble, according to a study by the Indian Institute of Astrophysics (announced on 3 November 2026)?
Show the answer
Answer: Visible Emission Line Coronagraph (VELC)
IIA scientists combined data from the Visible Emission Line Coronagraph (VELC), the primary payload among Aditya-L1's 7 payloads, with observations from NASA's SDO and three-dimensional modelling. VELC's spectroscopy in the 530.3 nm green emission line showed a Doppler pattern that a model with symmetric expansion could not reproduce, while a model with an inclined CME axis and asymmetric lateral expansion did.
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