Free Astronomy Magazine March-April 2026

50 MARCH-APRIL 2026 ASTRO PUBLISHING T his infographic depicts AT 2024- wpp, the brightest fast blue op- tical transient (FBOT) ever seen, and the likely mechanism behind its ex- treme power output. [NOIRLab/NSF/ AURA/R. Margutti/P. Marenfeld] large that you can’t power them with a core collapse stellar explosion — or any other type of normal stel- lar explosion,” says Natalie LeBaron, UC Berkeley graduate student and first author on the paper presenting the Gemini data. “The main mes- sage from AT 2024wpp is that the model that we started off with is wrong. It’s definitely not just an ex- ploding star.” The researchers hypothesize that the intense, high-energy light emitted during this extreme tidal disruption was a consequence of the long par- asitic history of the black hole binary system. As they reconstruct this his- tory, the black hole had been suck- ing material from its companion for a long time, completely enshrouding itself in a halo of material too far from the black hole for it to swal- low. Then, when the companion star finally got too close and was torn apart, the new material became en- trained into the rotating accretion disk and slammed against the exist- ing material, generating X-ray, ultra- violet, and blue light. Much of the gas from the companion also ended up swirling toward the poles of the black hole, where it was ejected as a jet of material. The team calculated that the jets were traveling at about 40% of the speed of light and gen- erated radio waves when they en- countered surrounding gas. Like most LFBOTs, AT 2024wpp is lo- cated in a galaxy with active star for- mation, so large stars like these are expected. AT 2024wpp is 1.1 billion light years away and between 5 and 10 times more luminous than AT 2018cow. The estimated mass of the compan- ion star that was shredded was more than 10 times the mass of the Sun. It may have been what’s known as a Wolf-Rayet star, which is a very hot and evolved star that has already used up much of its hydrogen. This would explain the weak hydrogen emission from AT 2024wpp. !