The collapse of a star's core is like compressing a spring: matter falls inward, and a neutron star is born at the center. But the fall is never perfectly smooth. In the boiling outer layers, random eddies transfer angular momentum to the infalling gas, and a disk swirls around the central object.
This disk is no calm river. It pulses, strengthening and fading. Gas without rotation keeps falling onto it from above, yet the disk doesn't vanish. It's saved by internal friction, which redistributes angular momentum, like a spinning top that keeps going because it's constantly nudged from the edges. Meanwhile, powerful jets blasting along the axis clear a path through the infalling gas, and the disk lives even longer.
That's how the explosion is born — not as a uniform sphere, but as a dance of jets choreographed by the disk. This picture helps explain the full variety of supernova remnants, from symmetric bubbles to chaotic tangles. The mechanism, dubbed "jittering jets," is becoming a key to understanding the deaths of massive stars.
as written by the authors arXiv:2607.20314
Motivated by observations of core-collapse supernova (CCSN) remnants that suggest cases where one to three energetic pairs of jets dominate the CCSN remnant morphology and, hence, the CCSN explosion energy, I examine the formation of long-lived intermittent accretion disks that launch such pairs of energetic jets in the framework of the jittering-jets explosion mechanism (JJEM). In the JJEM, pairs of jets explode all CCSNe. In most CCSNe, stochastic angular momentum fluctuations in the convective zones of the pre-collapse core seed instabilities above the newly born neutron star that lead to the formation of intermittent accretion disks. These disks launch several to about twenty pairs of jets that explode the star. CCSNRs with signatures of 1-3 very energetic pairs of jets require long-lived, intermittent accretion disks. I show that viscosity-driven angular momentum transport in the disk can prolong its lifetime even when material with zero angular momentum continues to feed the disk. In addition, the jets prevent matter from accreting from the polar direction, thereby extending the disk's lifetime. These two positive feedback processes, and the fluctuations that, in some cases, add up to a positive angular momentum, can substantially prolong the lifetime of 1-3 intermittent accretion disks (or none), which then launch the energetic pairs of jets. This study adds to the wide variety of morphologies that the JJEM can explain, hence strengthening the JJEM as the primary explosion mechanism of CCSNE.
The neutron star left behind after the explosion squeezes the mass of the Sun into a sphere the size of a city — about 20 kilometers. A teaspoon of its material would weigh a billion tons.
In Arthur C. Clarke's novel Rendezvous with Rama, humans explore a mysterious object that resembles a supernova remnant, riddled with internal structures.