Strange emissions similar to northern lights spotted on Sun

‘It’s an exciting discovery that has the potential to alter our comprehension of stellar magnetic processes’

Vishwam Sankaran
Tuesday 14 November 2023 11:49 GMT

Related video: The Sun Is Approaching Its Solar Maximum Much Sooner Than Expected and Scientists Don’t Know Why

Astronomers have spotted a stunning aurora-like display tens of thousands of miles above a dark and cold patch on the Sun.

The new type of radio emissions share properties with the northern lights spectrum commonly seen around Earth.

Fresh insights about the intense radiation bursts from the Sun have been described in a study published in the journal Nature Astronomy.

The discovery potentially opens new ways to understand similar phenomena in distant stars, said researchers, including those from the New Jersey Institute of Technology.

“This is quite unlike the typical, transient solar radio bursts typically lasting minutes or hours,” said study co-author Sijie Yu.

“It’s an exciting discovery that has the potential to alter our comprehension of stellar magnetic processes.”

Polar lights like the Aurora Borealis or Aurora Australis are visible across the sky on Earth closer to the North and South poles.

They occur as solar activities disturb the Earth’s magnetosphere, causing charged particles to precipitate along the polar regions, where the planet’s magnetic field converges.

The charged particles that converge here interact with oxygen and nitrogen atoms in the high atmosphere and generate intense radio emissions at frequencies of about a few hundred kilohertz (kHz).

In comparison, the newly observed solar radio emissions were detected over the temporary formation of a vast sunspot region where magnetic fields on the Sun’s surface are particularly strong.

The cooler and intensely magnetic sunspot areas provided a “favourable environment”, just like the magnetic polar caps on Earth, for these kinds of emissions to occur, scientists said.

“However, unlike the Earth’s auroras, these sunspot aurora emissions occur at frequencies ranging from hundreds of thousands of kHz to roughly 1 million kHz – a direct result of the sunspot’s magnetic field being thousands of times stronger than Earth’s,” explained Dr Yu.

Scientists said the radio bursts did not seem to be tied to the timing of the release of charged particles from the Sun as solar flares.

Instead, the sporadic emission of flares in nearby regions seemed to pump energetic electrons nearer to sunspots. These flares then powered the stunning radio emissions.

“We aim to determine if some of the previously recorded solar bursts could be instances of this newly identified emission,” said researchers.

“The characteristics resemble some of those observed on our planets and other distant stars, leading us to consider the possibility that this model could be potentially applicable to other stars with starspots,” said Bin Chen, another study author.

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