Imagine the Universe!
Imagine Home  |   Ask an Astrophysicist  |  
Ask an Astrophysicist

The Question

(Submitted February 16, 1998)

I just heard the term 'hypernova'. Do hypernovae really exist? Is it true that there was a recently discovered one? How does a hypernova form, in contrast to supernovae & black holes?

The Answer

A hypernova is a possible explanation for gamma-ray bursts. It can be thought of as a "failed supernova" -- a massive star whose core collapses but which doesn't quite blow itself apart. The idea is that the star's core collapses because it has run out of fuel and can no longer produce enough pressure to withstand gravity. The central part of the star collapses, forming either a neutron star or a black hole. In a supernova the resulting shockwave blows off the outer parts of the star. In the case of a hypernova the shock wave doesn't blow off the outer layers of the star. The material of the outer layers falls onto the central black hole or neutron star converting its gravitational potential energy to heat and radiation. This can result in a much higher luminosity than a supernova. This is why hypernovae were proposed as a possible explanation for gamma-ray bursts. The X-ray afterglow from a gamma-ray burst has been found to be more luminous than a supernova. Whether hypernovae actually exist is still an open question.

Damian Audley
for Ask an Astrophysicist

Previous question
Prev
Main topic
Main
Next question
Next

If words seem to be missing from the articles, please read this.

Imagine the Universe! is a service of the High Energy Astrophysics Science Archive Research Center (HEASARC), Dr. Alan Smale (Director), within the Astrophysics Science Division (ASD) at NASA's Goddard Space Flight Center.

The Imagine Team
Project Leader: Dr. Barbara Mattson
Curator: Meredith Gibb
Responsible NASA Official: Phil Newman
All material on this site has been created and updated between 1997-2014.
This page last updated: Thursday, 01-Dec-2005 13:58:40 EST