https://hubblesite.org/contents/news-releases/2023/news-2023-024#section-id-2
Copy text: "Among the rarest of these random cosmic events are a small class called Luminous Fast Blue Optical Transients (LFBOTs). They shine intensely in blue light and evolve rapidly, reaching peak brightness and fading again in a matter of days, unlike supernovae which take weeks or months to dim."
"The first LFBOT was found in 2018. Presently, they are captured once a year and so only a handful are known. There are several theories behind what causes the powerful explosions. But Hubble came along and made this phenomenon even more mysterious.
LFBOTs, they should blow up in the spiral arms of galaxies where star birth is underway. The massive newborn stars behind supernovae don't live long enough to go wandering off beyond their nesting ground inside a galaxy."