| Property | Type I | Type II |
| Origin | Binary system with one star a white dwarf | Massive dying star |
| Ejected mass (solar masses) | ~1 | ~5 |
| Velocity of ejected mass (km/s) | 10,000 | 5,000 |
| Total kinetic energy (J) | 1044 | 1044 |
| Visual energy (J) | few x 1042 | 1042 |
| Spectra | No hydrogen lines | Hydrogen lines |
| Corpse | Neutron Star | Neutron Star or Black hole |
| Frequency | 1 every 60 years | 1 every 40 years |