Hypernovae

Astronomers have detected events that we classify as “hypernovae.”

The word hypernova isn’t an official supernova classification but is widely used to describe the most energetic stellar explosions, usually linked to:

• Type Ic-BL supernovae (broad-lined Type Ic), where the progenitor star has lost its hydrogen and helium envelope.
• Long-duration gamma-ray bursts (GRBs), which are thought to be associated with hypernovae when a very massive star collapses to form a black hole and launches relativistic jets.

Key examples

• SN 1998bw (in ESO 184-G82):
  Associated with GRB 980425, this was the first well-established hypernova. It had unusually broad spectral lines, indicating high expansion velocities, and released about 10 times the energy of a typical core-collapse supernova.
• SN 2003dh (with GRB 030329):
  Another classic hypernova, cementing the GRB-hypernova connection.
• SN 2003lw (with GRB 031203):
  Very luminous, again tied to a GRB.
• SN 2016jca (with GRB 161219B):
  A more recent, well-observed hypernova-GRB pair.

How they’re detected

• Optical telescopes catch the supernova light curve and spectra.
• Satellites (e.g., Swift, Fermi) detect the associated gamma-ray bursts.
• Follow-up observations in radio and X-ray confirm the extreme energy release.
• Multiple hypernovae have been directly observed, usually through the combination of a bright supernova and a gamma-ray burst.