AI Catches a Black-Hole-Triggered Supernova (SN 2023zkd)

Astronomers say a star 730 million light-years away may have exploded while interacting with a black hole companion—and an AI system flagged the weird behavior early enough to watch the whole drama unfold.

Meet SN 2023zkd. First spotted by the Zwicky Transient Facility in July 2023, this supernova looked ordinary at first—until an AI system designed to find oddball light curves promoted it for follow-up. Months later, researchers realized the blast didn’t behave like typical supernovae: it showed a double-peaked light curve and, in archival data, a slow four-year brightening before the final detonation. That strange pre-game and the re-brightening after the blast point to a close-quarters interaction with a stellar-mass black hole nearby.

According to the team behind the discovery, the best-fit scenario is that the star was in a decaying orbit with a black hole. As the separation shrank, the hole siphoned material into a disk and stressed the star until it blew. An alternative is that the black hole completely shredded the star first, with the explosion’s light powered as debris slammed into dense gas around the system. Either way, the endgame leaves behind a heavier black hole—and a uniquely documented cosmic crime scene.

“Our analysis shows that the blast was sparked by a catastrophic encounter with a black hole companion, and is the strongest evidence to date that such close interactions can actually detonate a star.” — Alexander Gagliano, lead author (CfA / MIT) (press release)

Why this one matters

• AI assistant: Anomaly-spotting software (in the LAISS family) flagged the early weirdness so telescopes could swarm the target quickly (Live Science).
• Years of “pre-flare” activity: The system slowly brightened for ~1,500 days before the explosion—rare for supernovae and a clue to intense binary interaction (arXiv paper).
• Double peak: The blast brightened again ~240 days later, likely when the shock wave hit a thicker shell of gas ejected earlier (Washington Post).
• New class candidate: Reporters and researchers alike describe it as evidence for a new type of supernova triggered by black-hole interaction (Reuters).

How the light curve tells the story

Think of the system like a cosmic lathe. In the years before the explosion, the black hole’s gravity likely pulled off streams of gas, piling up two shells with different densities around the star. The first peak came when the supernova shock plowed through the inner, thinner material. Months later, a second peak flared as the shock reached the thicker outer shell—consistent with models for Type IIn supernovae interacting with dense circumstellar matter (ScienceAlert).

“Hidden” explosions AI can now catch

With the Vera C. Rubin Observatory about to survey the sky every few nights, astronomers expect many more of these rare, interaction-powered blasts. AI spotters will surface the oddballs in real time so teams can aim X-ray, optical, radio, and infrared telescopes while the action is still playing out (UC Santa Cruz).

Watch: quick explainers

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