How Supernovae Explode: New Model Reveals Star Instability Before Massive Outburst

How and why do supernovae explode? Those are questions that astronomers have been attempting to answer for years--with only some success. Now, though, scientists have created a new model of supernovae that may just answer these questions.

Supernovae are stellar explosions that can briefly outshine an entire galaxy. This luminous burst of radiation can expel much or all of a star's material, and can create a supernova remnant.

There are a few theories about supernovae explosions. Some scientists believe that supernovae first experience to an inward flow-since the star's core may collapse into a neutron star or a black hole-that is then superseded by a violent outward flow of the supernova explosion. This particular study, though, reveals that the star enters a global free fall following its loss of stability.

In this case, the researchers created a model of supernovae represented as a dynamical system subject to a loss of stability, just before they explode.  In this case, the researchers showed the stars' loss of stability can be described in mathematical terms as a dynamical saddle-node bifurcation. This particular approach makes it possible to create a universal equation to describe supernovae dynamics at its onset, taking into account the physical conditions of stability at the beginning of the explosion. This, in particular, sheds light on why supernova explosions last only between 10 to 30 seconds-a significantly shorter time than the overall pace of evolution of the star.

This research doesn't only have implications for supernovae, though. Because similar stability losses also occur in dynamical systems in nature, this model could be used to predict natural catastrophes before they happen. In fact, previous studies of the creeping of soft solids and earthquakes have already confirmed this approach could potentially be used.

The findings are published in The European Physical Journal E.