This orange dot is a gamma-ray burst, which appears to be a sign of an unusual event.
IT/A. Levan, A. Martin-Carrillo, et al.
The black hole that devoured the star appears to have taken revenge by devouring the star from the inside, causing a gamma-ray burst seen about 9 billion light-years from Earth.
The burst, dubbed GRB 250702B, was first discovered by NASA's Fermi Gamma-ray Space Telescope in July. Such bursts These are bright flashes caused by jets resulting from energetic events such as the collapse of massive stars into black holes or the merger of neutron stars, and they usually last no more than a few minutes.
However, GRB 250702B lasted 25,000 seconds – or about 7 hours – making it the longest known gamma-ray burst. Scientists have tried to explain this, but Eliza Knights at NASA's Goddard Space Flight Center in the US and her colleagues are now suggesting an unusual and rare possibility.
“The only one [model] What would naturally explain the properties observed in GRB 250702B is the collapse of a stellar-mass black hole onto the star,” the researchers write in a paper about their work.
In more typical long gamma-ray bursts, a massive star collapses to form a black hole, releasing jets after death. In this case, the team suggests the opposite: a pre-existing black hole evolved into a companion star whose outer layers expanded late in its life, causing the black hole to lose angular momentum and fall toward the star's core.
The black hole would then consume the star from the inside, creating the powerful jets seen as GRB 250702B and possibly causing a faint supernova, although too dim to be detected at that distance even by the James Webb Space Telescope.
This explanation makes sense for how such an ultralong burst could occur, he says. Hendrik van Erten at the University of Bath in the UK. “The argument made in this article is very compelling,” he says.
Knights and her colleagues hope that more events like this will be visible in the future thanks to new telescopes such as the Vera Rubin Observatory in Chile. For now, this gamma-ray burst remains “absurd,” Van Erten says.
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