SN 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...
SN Type characteristics guess at progenitor
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Ia no hydrogen in spectrum white dwarf that accretes
strong absoption at 6550 A > Chandrasekhar mass
near max light two white dwarfs that
late-time spectrum iron-group collide
emission lines
Ib no hydrogen in spectrum massive star which has
absorption near 5700 A, due to been stripped of H
He (plus other He lines) before core-collapse?
late-time spectrum emission from Wolf-Rayet star?
OI, CaII
Ic no hydrogen in spectrum massive star which has
no helium in spectrum been stipped of H and
late-time spectrum emission from He before core-collapse
OI, CaII Wolf-Rayet star?
II-P hydrogen in spectrum, massive red supergiant
with P-Cyngi profile
light curve has plateau for 30-90
days soon after max light
II-L hydrogen in spectrum, weak or less massive supergiant?
no P-Cygni profile lost some of envelope?
light curve falls linearly after
max light
IIb hydrogen in spectrum, but not much massive star which has
helium in spectrum lost MOST (but not
late-time spectrum emission from all) of its H
OI, CaII, plus H envelope (in binary?)
IIn hydrogen in spectrum, with narrow massive star which sits
emission lines on top of in middle of massive
broad emission features stellar outflow?
slow decline in light curve at
late times
strong radio emitter? some aren't
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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