In this artist’s rendering, the yellow depicts the material that is expelled just days after the stellar explosion. (Illustration: Bill Saxton, NRAO/AUI/NSF)
A nova occurs in a star that is part of a binary system – two stars orbiting one another. One star, known as a dense white dwarf, steals matter from the other and the interaction triggers a thermonuclear explosion that flings debris into space.
It was from this explosion from a system known as V959 Mon, located some 5,000 light years from Earth, that the researchers think the gamma rays were emitted.
This activity was first detected two years ago by NASA’s Fermi Gamma-ray Space Telescope. Also about that same time similar activity was being picked up by land-based radio telescopes around the world.
Since that initial detection by Fermi, which occurred in2012, the spacecraft has detected gamma rays from three additional nova explosions in other star systems.
“This mechanism may be common to such systems,” said Chomiuk. “The reason the gamma rays were first seen in V959 Mon is because it’s closer to us.”
Because the type of ejection detected in V959 Mon also is seen in other binary star systems, the new insights might help astronomers understand how those systems develop.
“We may be able to use novae as a ‘testbed’ for improving our understanding of this critical stage of binary evolution,” Chomiuk said.
Gamma rays can be dangerous and are capable of killing living cells. The medical field uses gamma rays, along with X-rays and other forms of high-energy radiation, to treat cancer.
Fortunately, by the time gamma rays travel across the universe to us, they are absorbed by the Earth’s atmosphere.