Calcium-rich supernova

In astronomy, a calcium-rich supernova (or Calcium-rich transient, Ca-rich SN) is a subclass of supernovae that, in contrast to more well-known traditional supernova classes, are fainter and produce unusually large amounts of calcium. Since their luminosity is located in a gap between that of novae and other supernovae, they are also referred to as "gap" transients. Only around 15 events have been classified as a calcium-rich supernova (as of August 2017) – a combination of their intrinsic rarity and low luminosity make new discoveries and their subsequent study difficult. This makes calcium-rich supernovae one of the most mysterious supernova subclasses currently known.