Dead star collision causes stellar explosion like nothing seen before – CNET

An artist’s animation of an eclipsing binary star system.

Caltech/IPAC

For years, a strange glimmer of light radiating from deep within the night sky had puzzled astronomers. Some meticulously tracked it, and slowly realized what the light revealed — the record of a star’s corpse that barreled into its companion star and forced it to blow up as a huge stellar explosion, or supernova.

The astonishing chain reaction happened in 2014, but its evidence only just reached Earth due to the rate at which light travels across space, according to researchers who published details of the saga in the journal Science on Thursday. 

“Theorists had predicted that this could happen, but this is the first time we’ve actually seen such an event,” the study’s lead author Dillon Dong, a graduate student at California Institute of Technology, said in a statement.

About 300 years ago, the researchers say, the massive star-carcass entered the vicinity of the smaller, living star and made the latter its companion. And so began their death dance.

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This illustration shows a massive star that’s about to explode. The explosion was triggered after its dead-star companion (a black hole or neutron star) plunged into the star’s core.

Chuck Carter

The huge corpse star that pulled the other stellar object into the land of the dead could either have been a black hole, which has a gravitational intensity so high it violently sucks everything into its abyss, or a neutron star. Neutron stars are rather powerful, too. They’re made up almost exclusively of neutrons — a tablespoon of one would equal the weight of Mount Everest.

After both stars whirled around each other for centuries, they collided. That collision is what provoked the living star’s explosion, or supernova. The supernova resulted in a bright jet protruding from the core of the star as the object collapsed into itself, suddenly illuminating the space surrounding it. 

The luminescence formed the glimmer detected by Dong’s team in the form of short-lived radio waves that were then compared with an X-ray spectrum of the sky. Data was collected from the Very Large Array Sky Survey (VLASS), which intends to image about 80% of the sky in three phases over seven years.

Gregg Hallinan, a professor of Astronomy at Caltech said, “Of all the things we thought we would discover with VLASS, this was not one of them.”

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