I saw this recently on SlashGear – Scientists Just Made A Big Discovery About Black Holes: https://www.slashgear.com/821514/scientists-just-made-a-big-discovery-about-black-holes/. Longer article.
BY NADEEM SARWAR/APRIL 4, 2022
Last year, a team from The Ohio State University discovered an object that was said to be one of the smallest black holes ever seen, and also the one closest to Earth at just 1,500 light-years away. It was followed by the discovery of another object some 12,000 light-years away that was thought to be a single mass-gap black hole or a high-mass neutron star. It now appears these conclusions may be wrong. Researchers behind both the discoveries combined their datasets and noticed that the two objects, named Giraffe and Unicorn, are actually double-star systems, Science News reports.
What is remarkable here is that the stars have been observed at a never-before-seen evolutionary stage. Each system consists of two stars, one of which is an older red giant with a puffy atmosphere, while the other one is a much smaller sub-giant star in its late stages of stellar life. Interestingly, the distance between the two stars is small enough that the sub-giant appears to be sucking materials from the accompanying red giant due to gravitational pull.