Scientists witness a supernova shockwave's explosive journey through a dying star for the first time, revealing a surprisingly symmetrical detonation. This groundbreaking observation was made possible by a swift response from an international team, including Dietrich Baade from the European Southern Observatory (ESO), who secured time on the Very Large Telescope (VLT) in Chile just 26 hours after the supernova was detected by the Asteroid Terrestrial-impact Last Alert System (ATLAS). The star, a massive red supergiant with a mass 12-15 times that of our sun, met its fate as it exhausted its nuclear fusion reactions, leading to a gravitational collapse and the formation of a neutron star. The star's layers then fell and rebounded, causing an explosion that tore it apart. This internal disintegration resulted in a dramatic brightening, but due to the star's immense size, it took approximately a day for the shockwave to break through its visible surface. The team, led by Yang, was poised to capture this pivotal moment. Had they waited a day longer, they would have missed it entirely. Understanding the exact process of a star's self-destruction is crucial, and this observation provides valuable insights. The supernova's light polarization offered clues about the geometry of the breakout, with the explosion appearing flattened like an olive or grape. Crucially, the explosion maintained symmetry even when colliding with a ring of circumstellar material. These findings suggest a common physical mechanism driving the explosions of many massive stars, characterized by well-defined axial symmetry and large-scale action. The results will enable astronomers to refine models describing the shockwave's dynamics in supernova explosions. Specifically, some models propose that the shockwave gains energy by absorbing neutrinos as it travels from the core to the star's surface. However, neutrino absorption should lead to highly asymmetrical explosions, which contradicts the observed symmetry. The team suggests that powerful magnetic fields might shape the asymmetry in cases where later-stage supernova explosions exhibit asymmetry. The study's findings were published in Science Advances on November 12 and are available on the ESO website.
