Astronomers identify the coldest star yet that emits radio waves

Astronomers using data collected by our ASKAP telescope have shown that a small, faint star is the coldest on record to produce emission at radio wavelength.

The ‘ultracool brown dwarf’ examined in the study is a ball of gas simmering at about 425 degrees centigrade – cooler than a typical campfire – without burning nuclear fuel. By contrast, the surface temperature of the Sun, a nuclear inferno, is about 5600 degrees.

While not the coldest star ever found, it is the coolest so far analysed using radio astronomy. The findings are published today in The Astrophysical Journal Letters.

Lead author and PhD student in the University of Sydney's School of Physics, Kovi Rose, said it's very rare to find ultracool brown dwarf stars like this producing radio emission, because their dynamics do not usually produce the magnetic fields that generate radio emissions detectable from Earth.

“Finding this brown dwarf producing radio waves at such a low temperature is a neat discovery," Rose said.

“Deepening our knowledge of ultracool brown dwarfs like this one will help us understand the evolution of stars, including how they generate magnetic fields," he said.

Added by James Chesters on 2023-07-14