Most supernovae are caused by stars collapsing at the end of their lives to create black holes or dense neutron stars. But those outcomes are apparently not true for two recently found supernovae that are much farther away and brighter than almost any star explosion ever seen.
Astronomers were initially mystified. But a new study posits that the oddball supernovae may have ended up as highly magnetic, rapidly spinning objects called magnetars. [M. Nicholl et al, Slowly fading superluminous supernovae that are not pair-instability explosions, in Nature]
A magnetar can rotate as fast as the blades of a kitchen blender. The huge amount of energy tied up in their spin could then be released in a torrent that would make them shine 100 times brighter than a normal supernova.
A project called the Supernova Legacy Survey discovered the objects. They belong to a newly designated class called superluminous supernovae, which account for just one in every 10,000 supernovae. Yet their extreme brilliance means we can see them from much farther away than usual.
For instance, one is about 10 billion light-years away and dates from the very early universe. So in a way, this discovery is really old news.
[The above text is a transcript of this podcast.]
[Scientific American is part of Nature Publishing Group.]