Unusual supernovae may be caused by magnetars

Ars Technica : Supernovae are so bright that they can outshine entire galaxies. The brightest of them are known as superluminous supernovae and are usually caused by the explosions of stars more than 100 times as massive as the Sun or through a process called pair instability . Two recently identified superluminous supernovae didn’t match the usual characteristics of either process. An analysis of the explosions by an international team of astronomers revealed a similarity with explosions caused by the compression and heating of material surrounding magnetars—pulsars with extremely strong magnetic fields. The observations showed that both supernovae had lower than expected concentrations of heavy elements, suggesting that the explosions were not from highly massive stars. However, the supernovae also brightened significantly faster than pair-instability supernovae and had a noticeable presence of blue wavelength light, which is not a pair instability characteristic either. The two unusual supernovae did display a high level of ionized material, indicating very high temperatures, which is common following the formation of magnetars.