First-Ever View of a Supernova's Birth: VLT Captures Olive-Shaped Explosion

First direct observations of a supernova's earliest hours reveal an olive-shaped blast

Scientists have, for the first time, directly observed the very early hours of a supernova and found the explosion produced a striking, vertically oriented olive-like shape rather than a simple sphere. The discovery offers new constraints on how massive stars end their lives.

Rapid response with a powerful telescope. Using the European Southern Observatory’s Chile-based Very Large Telescope (VLT), researchers targeted a red supergiant about 15 times the mass of the Sun that exploded in the galaxy NGC 3621, roughly 22 million light-years away in the direction of the constellation Hydra. The event was first detected on April 10, 2024; within hours astrophysicist Yi Yang of Tsinghua University requested VLT time and the telescope obtained observations just 26 hours after discovery — 29 hours after the explosion’s shock first broke through the star’s surface.

What the team saw. The VLT images and spectra show the doomed star surrounded at its equator by a pre-existing disk of gas and dust. As the inner material accelerated outward, the outflow was concentrated at opposite sides of the star rather than expanding uniformly. That produced a non-spherical, vertically oriented olive-like silhouette during the short-lived shock-breakout phase.

“The geometry of a supernova explosion provides fundamental information on stellar evolution and the physical processes leading to these cosmic fireworks,” said Yi Yang, lead author of the study published in Science Advances.

Physical details. The progenitor was a red supergiant about 25 million years old and roughly 600 times the Sun’s diameter. Some of its mass was ejected into space by the explosion; the remaining core is believed to have collapsed into a neutron star, according to co-author Dietrich Baade of the European Southern Observatory. A light-year — the distance light travels in one year — is about 5.9 trillion miles (9.5 trillion kilometers).

Why it matters. Capturing the shock-breakout phase is extremely difficult because it unfolds so quickly. Observations during this brief window provide a direct view of how material accelerated at the star’s center pierces the photosphere and escapes into space. The non-spherical shape observed in this case appears to rule out some existing theoretical models and gives astrophysicists new constraints on the mechanisms that trigger explosions in massive stars.

Broader context. Massive stars (those exceeding roughly eight times the Sun’s mass) end their lives in core-collapse supernovae, a process that is still not fully understood. Early, high-resolution observations such as these are essential to refine models of stellar death and the formation of compact remnants like neutron stars and black holes.

Study published in Science Advances. Reporting by Will Dunham; editing by Daniel Wallis.