Artist’s impression of a black hole destroying a nearby star – a phenomenon that could explain a new type of stellar explosion
ESA/C. Callereau
Astronomers have discovered a stunningly bright explosion in the sky unlike any supernova they’ve ever seen. The supernova brightens more than most known supernovae before fading so rapidly that researchers have named it a new type of object called a luminous fast cooler, or LFC.
Matt Nicol Doctors at Queen’s University Belfast in the UK used the ATLAS telescope network in Hawaii, Chile and South Africa to discover an object called AT2022aedm but nicknamed Adam. They then collaborated with other observatories around the world to make further measurements. Near the edge of a galaxy populated by older stars, Adam became hundreds of billions of times brighter than our Sun in just nine days. It then disappeared almost completely within a month. We expect a supernova this bright to fade to about half its peak brightness at the same time.
“It’s a combination of properties that doesn’t match any known type of object we’ve seen before,” says Nicol. “We’ve seen very bright supernovae, we’ve seen supernovae that fade very quickly, we’ve seen supernovae in old galaxies, and we’ve seen all three. I’ve never seen them at the same time.”
of The age of Adam’s main galaxy means that there are no large young stars prone to supernovae. The fact that Adam is located so far from the galactic center rules out the idea that it was caused by a process related to a supermassive black hole at the galactic center. When two stars collide, they don’t get very bright.
The remaining explanation is that Adam was caused by a rare intermediate-mass black hole shattering and engulfing a star. Star tearing processes are responsible for the brightening, and intermediate-mass black holes are expected to be fast-eating, which could explain the rapid dimming.
“It’s the hardest thing to eliminate, so it’s the biggest option left at the moment,” says Nichol. However, the observations are not in perfect agreement. He should produce X-rays when a star is shredded like that, but Adam produced very few X-rays. The challenge of explaining to Adam the oddity that he has no x-rays remains an obstacle to understanding the explosion.
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