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Science & TechSpace

Aditya-L1 shows a solar eruption swelling unevenly, a finding that could sharpen space weather forecasts

Bengaluru astronomers used the spacecraft's coronagraph to show that a coronal mass ejection in August 2024 did not grow like a neat bubble but bulged more on one side.

From the editorial desk · BengaluruPublished
The Sun imaged by the SUIT telescope on India's Aditya-L1 observatory (file photo)
The Sun imaged by the SUIT telescope on India's Aditya-L1 observatory (file photo)Photo: ISRO / Wikimedia Commons, CC0

Key points

  1. Aditya-L1's VELC instrument caught a solar eruption expanding asymmetrically, not as a uniform bubble.
  2. Only a 3-D model with a tilted axis and lopsided growth matched what the telescope saw.
  3. Uneven expansion can change when an eruption reaches Earth, the team says.

India’s first solar observatory has shown that an eruption from the Sun can swell more on one side than the other, a result its scientists say could help forecasters judge when such storms will hit Earth.

Astronomers at the Indian Institute of Astrophysics (IIA) in Bengaluru used the Visible Emission Line Coronagraph (VELC), the main instrument on Aditya-L1, to follow a coronal mass ejection that burst from near the Sun’s western edge on 5 August 2024. The study, released by the government on Tuesday afternoon, appears in The Astrophysical Journal Letters.

“Our results show that the CME did not expand uniformly,” the team said.

A coronal mass ejection erupting from the Sun (file photo)
A coronal mass ejection, the kind of solar eruption Aditya-L1's coronagraph followed in August 2024.NASA Goddard Space Flight Center / Wikimedia

VELC watches the Sun’s outer atmosphere in the green light of highly charged iron, which traces gas at about 1.8 million degrees Kelvin, close to the solar surface. Its Doppler readings showed material moving both towards and away from Earth in different parts of the cloud.

The researchers, led by PhD student Saurabh Tripathi with solar astronomer Tanmoy Samanta and Jayant Joshi, then built a three-dimensional model of the eruption. Only a version with a tilted axis and lopsided sideways growth matched the pattern. “A model with symmetric expansion could not reproduce the observed pattern,” the team said.

That matters beyond the telescope. How a cloud of solar plasma spreads affects the drag it feels in space, and so its speed and arrival time at Earth, where strong storms can disturb satellites, radio links and power grids.

VELC was built at IIA’s MGK Menon Lab for Space Sciences in Hosakote with ISRO’s support. Aditya-L1, launched in September 2023, watches the Sun from the L1 point between the Sun and Earth with seven instruments.

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