Blue cosmic flares traced to black-hole and Wolf-Rayet star mergers

Astronomers propose that the rare, fast-evolving blue explosions called Luminous Fast Blue Optical Transients (LFBOTs) arise when a compact stellar remnant—such as a black hole or neutron star—merges with the helium core of a Wolf-Rayet star. The Wolf-Rayet merger model neatly explains LFBOTs’ blue hue, dense circumstellar environments, and offsets from birth sites better than tidal disruption or standard supernova scenarios. With the Rubin Observatory’s LSST expected to uncover more LFBOTs at greater distances, scientists hope to test this channel and learn how these progenitors evolve over cosmic time.