Space Grant Consortium - University of Wisconsin - Green Bay

Understanding the Evolution of Supernova Progenitors
Cyrus M. Vandrevala 1, 2 , Bradley T. Rentz 1 , Christopher J. Stockdale 2
Milwaukee, WI
Marquette University
Stefan Immler
Greenbelt, MD
NASA Goddard Space Flight Center/Universities Space Research Association
Kurt W. Weiler 3
Washington D.C.
Naval Research Laboratory
Abstract
We
present
the
results
of
radio
and
X­ray
observations
of
the
Type
IIb
supernovae
SN
2008ax,
SN
1993J,
and
SN
2001ig.

Though
they
are
all
Type
IIb
supernovae,
SN
2008ax
and
SN
2001ig
have
radio
decay
patterns
which
show
bumps
on
the
decline
of
the
curve
while
SN
1993J
has
a
smooth
radio
light
curve
which
suddenly
drops
off.
 
Additionally,
SN
2008ax
and
SN2001ig
have
fast
radio
and
X­ray
evolutions
on
the
order
of
hundreds
of
days,
while
SN
1993J
shows
a
much
longer
evolution
on
the
order
of
thousands
of
days.
Introduction
Type IIb supernovae (SNe), first discovered by Woosley et al. (1987), were thought to be the
result of the collapse of a Type Ib SN progenitor that has a small hydrogen envelope. They are
very rare since only ~40 have been discovered in the last couple of decades and only a few are
well observed. Our research concentrates on these supernovae for two primary reasons:
1) These supernovae may be the evolutionary link between Type II supernovae (which have
observed hydrogen spectra) and Type Ib/c supernovae (which have no observed hydrogen
lines) as suggested by Woosley et al. (1987).
2) However, not all Type IIb supernovae evolve in the same manner; we are trying to
determine if the current classification of Type IIb supernovae needs to be re-evaluated.
Background
Supernovae
A
 supernova
 is
 the
 catastrophic
 end
 of
 the
 life
 of
 a
 very
 massive
 star
 that
 can
 create
1
Funding provided by the Wisconsin Space Grant Consortium (WSGC) and the National Space Grant College and
Fellowship Program (NSGC)
2
Sponsored by NASA award NNX 09AC90G
3
KWW thanks the Office of Naval Research for the 6.1 funding that supports his work
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