![eutron star surpasses 3 solar masses eutron star surpasses 3 solar masses](http://burro.astr.cwru.edu/Academics/Astr221/LifeCycle/neutstruct.gif)
Most of the energy released is actually in the form of neutrinos, only 1% is in the form of visible light.
![eutron star surpasses 3 solar masses eutron star surpasses 3 solar masses](https://www.tpi.uni-jena.de/~bernuzzi/img/2110.06957.png)
A total of 10 46 J is released in a matter of seconds, 50 × more than the Sun will release in 10 billion years on the main sequence. In the collapsing massive star the energy involved is vastly greater than you running in to a wall. This is similar to what would happen if you run headlong into a wall - you bounce back. The surrounding material is still collapsing, however, and slams into the now solid, rigid core and rebounds, forming a massive shockwave. Neutron degeneracy pressure actually stops the inward collapse of the core. Once the temperature reaches 10 12 K the neutrons become degenerate. There is therefore no more electron degenerate pressure so the core collapse continues. Massive stars basically live fast, die young and go out with a bang.
![eutron star surpasses 3 solar masses eutron star surpasses 3 solar masses](https://universe-review.ca/I08-08-SNtypes2.png)
Identified by the presence of hydrogen lines in their spectra, Type II supernovae are thought to be due to the core collapse in massive stars as explained below. These are massive stars, typically about 20 solar masses or higher, that explode, reaching luminosities of about 10 9 × solar luminosity or a magnitude of about -17 at maximum brightness for a few days before fading over several weeks. When it exploded as Supernova 1987A it captured the attention of astronomers from around the world. Sanduleak -69° 202 was a blue supergiant with a mass of about 18 solar masses in the Large Magellanic Cloud. Since observed extensively at all wavebands, SN1987A has helped astronomers better understand the death of massive stars. The object, named Supernova 1987A, was a massive star ripping itself apart in a violent event that released as much energy for a short period as the rest of the galaxy combined. What was remarkable was that this was the first naked-eye supernova (SN) visible since 1604. In February 1987 a new star appeared in the Large Magellanic Cloud, a neighbouring galaxy 170,000 light years away. M1, the Crab Nebula, the remnant of a supernova that exploded in AD 1054.