An axisymmetric shock breakout indicated by prompt polarized emission from the type II supernova 2024ggi.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41223284.
- Also identified by DOI 10.1126/sciadv.adx2925 and PMC identifier 13142702.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The death of massive stars is triggered by an infall-induced bounce shock that disrupts the star. How such a shock is launched and propagates through the star is a decade-long puzzle. Some models assume that the shock can be reenergized by absorbing neutrinos, leading to highly aspherical explosions. Other models involve jet-powered shocks that lead to bipolar explosions reflected in the geometry of the shock-breakout emission. We report measurement of the geometry of the shock breakout through unprecedentedly early spectropolarimetry of the nearby type II supernova 2024ggi starting ~1.2 days after the explosion. The measurement indicates a well-defined symmetry axis of the shock breakout, which is also shared by the hydrogen-rich envelope that emerged after the circumstellar matter was engulfed by the ejecta, revealing a persisting and prominent symmetry axis throughout the explosion. These findings suggest that the physical mechanism driving the explosion of massive stars manifests a well-defined axial symmetry and acts on large scales.