Supernova SN 2022esa suggests massive stars can explode as they form black holes.

Researchers observed SN 2022esa, a rare type Ic-CSM supernova from a very massive star that produced a bright explosion while forming a black hole; its light showed a stable monthly periodicity that points to a binary progenitor.

Researchers at Kyoto University studied SN 2022esa, a rare and bright supernova linked to an extremely massive star. Observations used the Seimei telescope in Okayama and the Subaru telescope in Hawaii. The event was classified as type Ic-CSM and showed a bright explosion even as the star was on the path to becoming a black hole. The light curve also displayed a regular monthly signal before the final explosion. Key observations: - SN 2022esa was identified as a type Ic-CSM supernova and monitored with Seimei and Subaru. - The progenitor appears to have been extremely massive and luminous, yet produced a bright explosion while forming a black hole. - The supernova's light curve showed a clear, stable periodicity of about one month prior to the final explosion. - The regular pre-explosion eruptions point to a binary companion, either another massive star or possibly a black hole, driving the pattern. - The researchers conclude the system would likely evolve into a binary pair of black holes, a source class relevant to gravitational-wave observatories such as LIGO. Summary: This result indicates that at least some very massive stars can announce their collapse into black holes with luminous explosions, and that binary interactions can drive regular pre-explosion eruptions. The finding offers a new direction for understanding the formation history of black-hole binaries and their role as gravitational-wave sources. Undetermined at this time.