Scientists have modelled the supernova that results as a pulsating supergiant’s life ends, with the potential of showing us what is happening with Betelgeuse.

Whilst astronomers are still diligently studying Betelgeuse with the hope of discovering what is causing the red supergiant’s surface to rapidly dim, physicists from UC Santa Barbara have devised a model to show the process that a dying star undergoes as it reaches the end of its life and goes supernova.

When a star the size of Betelgeuse — ten times that of the Sun — reaches the end of its life cycle its ‘death’ is marked by a spectacular and powerful explosion. These supernova events can be so luminous that they often outshine the entire light output of the galaxy in which the star sits. Betelgeuse’s dipping brightness has some astronomers theorising that this is the process which it is currently undergoing, but there are other explanations currently being posited.

Supernovae are stupendously energetic; many can briefly outshine an entire galaxy. Artist’s impression. (ESO/M. KORNMESSER)

It is very probable that Betelgeuse will go supernova within the next million years, sooner if this group of astronomers are correct, resulting in a spectacular display that will be visible from Earth, even during daylight.

Betelgeuse is a member of a family of stars calling pulsating semiregular variable stars. Even before this recent period of extreme dimming was observed, dimming as a result of the pulsating nature of the red supergiant had been observed. In fact, it is a well-known characteristic amongst red supergiants.

So much so, that researchers at UC Santa Barbara had already begun work making predictions about the brightness of the supernova that would result when a pulsating star explodes before the Betelgeuse was speculated to be undergoing such a process.

“We wanted to know what it looks like if a pulsating star explodes at different phases of pulsation,” explains physics graduate student Jared Goldberg. “Earlier models are simpler because they don’t include the time-dependent effects of pulsations.”

Goldberg, a National Science Foundation graduate research fellow, has authored a paper detailing a new model of how a star’s pulsation will affect the ensuing explosion as it reaches the end of its life with ars Bildsten, director of the campus’s Kavli Institute for Theoretical Physics (KITP) and Gluck Professor of Physics, and KITP Senior Fellow Bill Paxton. The paper is published in the Astrophysical Journal.