A group of scientists discovered long-duration radio signals on sunspots. Radio signals were detected from the sunspot at an altitude of approximately 40,000 kilometers. This is the first to observe such radio signals on the Sun; Long-duration radio signals have previously been detected on other planets or stars.

“This is the first detection of this type of sunspot radio emission,” said lead author Siji Yu of the New Jersey Institute of Technology.

The discovery of long-duration radio signals from the Sun will help scientists better understand our star and study the processes underlying radio signals, as well as the processes occurring in distant stars. The Sun regularly emits short radio bursts that can last from a few minutes to several hours.

But the radio burst observed by scientists lasted more than a week; this lasted much longer than normal short radio bursts. The researchers made the observations using 27 radio telescopes combined into a “Very Large Array” (VLA) in New Mexico.

Radio bursts, in addition to duration, have spectrum and polarization characteristics similar to auroras on Earth, resulting from the interaction of solar particles with the planet’s magnetic field. On Earth, as on Jupiter and Saturn, auroras result from the interaction of solar particles with a magnetic field, which attracts and accelerates the particles to the poles where the magnetic field’s lines of force meet.

As solar particles accelerate towards the poles, they emit intense radio signals at a frequency of several hundred kilohertz. When they reach the planet’s atmosphere, they interact with atmospheric atoms, creating an aurora.

Scientists analyzed the data to examine the properties and nature of long radio bursts detected on sunspots. The results showed that the radio bursts probably occurred as a result of processes similar to the process of formation of the “aurora borealis”. Energetic electrons become trapped in the magnetic field created by the sunspot. Once the particles enter the field, they are accelerated in the direction of the sunspot where the magnetic field lines meet, creating radio signals.

Unlike the “aurora borealis” on Earth, Jupiter, and Saturn, radio bursts on sunspots occur at much higher frequencies, around one million kilohertz; This is a significant difference from the usual hundreds of thousands of kilohertz at which auroras occur on Earth.

“This is a direct result of the sunspot’s magnetic field being thousands of times stronger than the Earth’s magnetic field,” Yu explained.

In the coming weeks and months, the team will reexamine other bursts of solar radio emission to determine whether they are similar to the long bursts detected by the VLA.

“We have an excellent opportunity to investigate the sources of such radio bursts thanks to NASA’s growing fleet of heliophysical missions, such as the Solar Dynamics Observatory [SDO] “It’s constantly monitoring active regions on the Sun that could cause this phenomenon,” said heliophysicist Nachimutuk Gopalswamy of NASA’s Goddard Space Flight Center.