Scientists Record Earliest Stage of Supernova Blast

Star’s explosion exhibited a distinctive olive-like shape
The doomed star was 15 times more massive than the sun
It was located about 22 million light-years from Earth

Astronomers have captured the earliest moments of a supernova for the first time, offering new insight into one of the universe’s most violent events. Using the Very Large Telescope (VLT) in Chile, researchers observed a massive star in the NGC 3621 galaxy, located 22 million light-years away in the Hydra constellation. The star, about 15 times the mass of the sun, erupted in a shape resembling a vertically standing olive. This distinctive geometry challenges long-held assumptions about how such explosions unfold.

Rapid Detection and Observation

The supernova was first detected on April 10, 2024, coinciding with astrophysicist Yi Yang’s arrival in San Francisco. Within hours, Yang requested that the VLT be directed toward the event, a request that was quickly approved. Observations began just 26 hours after detection and 29 hours after material from inside the star broke through its surface. Capturing the explosion at this stage allowed scientists to study its initial breakout shape before it interacted with surrounding matter.

Instead of a spherical blast, the explosion pushed outward in opposite directions. A preexisting disk of gas and dust around the star’s equator distorted the blast, producing the olive-like form. This rare observation provided evidence that external material can significantly influence the geometry of a supernova. Yang emphasized that the shape offers clues about the processes triggering the explosion deep within the star.

Life and Death of a Red Supergiant

The star was a red supergiant, a type known for relatively short lifespans compared to smaller stars. At the time of its death, it was about 25 million years old and had a diameter 600 times greater than the sun. Some of its mass was expelled into space, while the remainder likely collapsed into a neutron star, one of the densest objects in the universe. Co-author Dietrich Baade of the European Southern Observatory explained that such remnants are highly compact and mark the final stage of stellar evolution.

Supernovae occur when a star exhausts its hydrogen fuel, causing its core to collapse and triggering a powerful outward shock. The VLT captured the moment this shock broke through the star’s surface, releasing immense energy. During this brief phase, the explosion brightens dramatically and becomes observable. Studying this stage helps scientists refine models of how massive stars die.

Implications for Stellar Physics

Understanding the geometry of supernovae is critical for advancing theories of stellar evolution. The olive-shaped blast suggests that surrounding material plays a larger role than previously thought. Yang noted that the findings may rule out some existing models of the explosion process. Researchers continue to debate the exact mechanisms behind supernovae in stars more than eight times the mass of the sun.