Supernova Taxonomy

Michael Richmond
May 12, 1996

Well, the "splitters" have been beating the "lumpers" in the SN classification business lately, so there is some new terminology. Let me exercise my memory here...


Supernovae Classifications
SN Type Characteristics Guess at Progenitor
Ia
  • No hydrogen in spectrum
  • Strong absorption at 6550 A (Angstroms) near max light
  • Late-time spectrum iron-group emission lines
  • White dwarf that accretes > Chandrasekhar mass
  • Two white dwarfs that collide
Ib
  • No hydrogen in spectrum
  • Absorption near 5700 A, due to He (plus other He lines)
  • Late-time spectrum emission from O-I, Ca-II
  • Massive star which has been stripped of H before core-collapse?
  • Wolf-Rayet star?
Ic
  • No hydrogen in spectrum
  • No helium in spectrum
  • Late-time spectrum emission from O-I, Ca-II
  • Massive star which has been stripped of H before core-collapse?
  • Wolf-Rayet star?
II-P
(plateau)
  • Hydrogen in spectrum, with P-Cygni profile
  • Light curve has plateau for 30-90 days soon after max light
  • Massive red supergiant
II-L
(linear)
  • Hydrogen in spectrum weak or no P-Cygni profile
  • Light curve falls linearly after max light
  • Less massive supergiant?
  • Lost some of envelope?
IIb
  • Hydrogen in spectrum, but not much
  • Helium in spectrum
  • Late-time spectrum emission from O-I, Ca-II, plus H
  • Massive star which has lost MOST (but not all) of its H envelope (in binary?)
II-n
  • Hydrogen in spectrum, with narrow emission lines on top of broad emission features
  • Slow decline in light curve at late times
  • Massive Star which sits in middle of massive stellar outflow?

There's also a paper in a recent A&A which suggests a new classification scheme (based primarily on light curve properties?), but it hasn't been widely adopted, as far as I know.

The old Zwicky classes (types III, IV, V) are not used at all at the current time, as far I as know.

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