Newswise — ITHACA, N.Y. – After a distant star’s explosive death, an active stellar corpse was the likely source of repeated energetic flares observed over several months – a phenomenon astronomers had never seen before.
The findings are detailed in Cornell University-led research published Nov. 15 in Nature.
The bright, brief flashes appeared in the aftermath of a rare type of stellar cataclysm, known as a luminous fast blue optical transient, or LFBOT.
Astronomers have speculated about what might drive such extreme explosions, which are far brighter than the violent ends massive stars typically experience but fade in days instead of weeks. The research team believes the previously unknown flare activity, which was studied by 15 telescopes around the world, confirms the engine must be a stellar corpse: a black hole or neutron star.
“We don’t think anything else can make these kinds of flares,” said Anna Y. Q. Ho, assistant professor of astronomy at Cornell. “This settles years of debate about what powers this type of explosion and reveals an unusually direct method of studying the activity of stellar corpses.”
Ho is the first author of “Minutes-duration Optical Flares with Supernova Luminosities,” published with more than 70 co-authors who helped characterize the LFBOT officially labeled AT2022tsd and nicknamed “the Tasmanian devil,” and the ensuing pulses of light seen roughly a billion light years from Earth.
Ho hopes the research advances longstanding goals to map how stars’ properties in life may predict the way they’ll die, and the type of corpse they produce.
In the case of LFBOTs, rapid rotation or a strong magnetic field likely are key components of their launching mechanisms, Ho said. It’s also possible that they aren’t conventional supernovas at all, instead triggered by a star’s merger with a black hole.
“We might be seeing a completely different channel for cosmic cataclysms,” she said.
The unusual explosions promise to provide new insight into stellar lifecycles typically only seen in snapshots of different stages – star, explosion, remnants – and not as part of a single system, Ho said. LFBOTs may present an opportunity to observe a star in the act of transitioning to its afterlife.
“Because the corpse is not just sitting there, it’s active and doing things that we can detect,” Ho said. “We think these flares could be coming from one of these newly formed corpses, which gives us a way to study their properties when they’ve just been formed.”
For additional information, see this Cornell Chronicle story.
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