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Astronomers Discover Small But Powerful ‘Micronova’ Star Burst


Each micronova can burn “about 3.5 billion Great Pyramids of Giza” of matter (or 20,000,000 billion kilograms) in just a few hours, the researchers say.

These extremely powerful explosions can occur on the surface of white dwarfs or dead stars roughly as small as our planet, according to observations made by a team of astronomers using the Very Large Telescope at the European Southern Observatory. in the Atacama Desert in Chile.

“We have discovered and identified for the first time what we call a micronova,” said study lead author Simone Scaringi, an astronomer and assistant professor at Durham University in the UK, in a statement. “The phenomenon challenges our understanding of how thermonuclear explosions in stars occur. We thought we knew, but this discovery offers a completely new way of making them happen.”

A study detailing the findings published Wednesday in the journal Nature.

Strong magnetic fields

White dwarf stars that find themselves associated with other stars draw hydrogen from their companions, like zombies feeding on their other stars. When the gas meets the hot surface of the white dwarf, the hydrogen atoms fuse into helium, triggering an explosion. These events are known as novae.

“Such detonations cause the entire surface of the white dwarf to burn and glow for several weeks,” study co-author Nathalie Degenaar, an astronomer and assistant professor at the University of Amsterdam, said in a statement.

Micronovae are smaller than typical novae and only last a few hours.

Micronova explosions occur on white dwarfs that have strong magnetic fields, which send material toward the poles of the star. This trajectory causes hydrogen fusion reactions to occur in more localized locations at the magnetic poles.

Astronomers Discover Small But Powerful ‘Micronova’ Star Burst

“This leads to the explosion of micro-fusion bombs, which are about one millionth the force of a nova explosion, hence the name micronova,” said study co-author Paul Groot. , astronomer and professor at Radboud University in the Netherlands, in a statement. .

Tracking Intense But Brief Events

The research team spotted the microexplosions after reviewing data collected by NASA’s Transiting Exoplanet Search Satellite, or TESS mission. The satellite is used to search for exoplanets, but it also monitors nearby stars to search for planets around them.

Astronomers Discover Small But Powerful ‘Micronova’ Star Burst

“While sifting through astronomical data collected by NASA’s TESS, we discovered something unusual: a bright flash of optical light lasting a few hours. Searching further, we found several similar signals,” Degenaar said.

Two of the micronovae occurred on white dwarfs, and astronomers tracked the third using the Very Large Telescope to confirm it was also a white dwarf. This allowed the researchers to declare that their observations were the discovery of something new.

Now that micronovae are their own class of stellar explosions, the research team hopes to observe more of them to see how common they are, especially as they challenge the current understanding of star explosions.

“It shows how dynamic the universe is. These events can actually be quite common, but because they’re so fast-paced, they’re hard to capture in action,” Scaringi said.


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