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SNe
(Informal) workshop - Ferrara April 2004
Astrophysical (natural) Explosive Devices
Thermonuclear SNe
Gravitational collapse
He-detonation
C-deflagration
C-delayed detonation
Induced Core collapse
(nuclear runaway fails)
Pair instability, core collapse & O explosion
(core collapse fails)
SNe Classification
II p
Type II
Core
collapse of
massive
stars
II L
SNe
I b (strong He)
I c (weak He)
Type I
I a (strong Si)
Thermonuclear
explosion
based on spectra and light curves morphologies
Type Ia light curve
Riess et al. , 1997
Brighter
Slower Decline
Dimmer
Faster Decline
standard candles
visible up to z ~ 1
DL
 High-z Team
(Brian Schmidt & co)
 Supernova
Cosmology Project
(Saul Perlmutter & co.)
0.25 mag fainter
than for an
EMPTY Universe
Fainter  Further
z
The Universe is Accelerating
1
qo  M   
2
Type IIp light
curve:
potential
standard
candles up to
z~5
(with NGST)
The virial theorem: stellar core evolution
2
M dM
GM
  G 
 q
 3P V
r
R
M R M
q
d
 1.5
r M M
R
r
r
g
0
1
r
4
3
PM R r M
2
4
2
3
r
0
log P
Non-degenerate
r4/3
relativistic
M2
M1
r5/3
Non-relativistic
log r
MCh  5.83Ye2
if
Ye  0.5  MCh  1.457
Stellar evolution
M<0.8 M
t>1/HO
0.8<M/M<8
15 Gyr<t<30 Myr
0.5<Mf /M<1.1
CO WD
8<M/M<11
t.1030 Myr
Mf =1.2-1.3 M
ONeMg WD
11<M/M<100
t. 1-10 Myr
Mf =1.2-2.5 M
Fe (Ye.0.45)
collapse NS or BH
M>100 M
t#1 Myr
O (pair jnstability)
(Ye=0.5)
may or may not explode
He-burning: the competition between
3a -> 12C and 12C+a ->16O+g
4He
5 M
Z=0.02
Y=0.28
12C
16O
Na<s,v> (10-15 cm3mol-1s-1)
for T9=0.2
Low
ECM (keV)
Adop. high
Kunz et al
2001
5.25
7.58
10.2
Buchman
n 1996
3.04
7.04
13.04
NACRE
5.44
9.11
12.8
3195
2685
2418
CF85
4.74
Jp
10957
0-
10367
4+
9847
9580
2+
1-
8872
2-
7117
6917
12+
6130
3-
6049
0+
0
0+
Q = 7.162 MeV
Gamow peack energies
12C+4He
CF88
Ex (keV)
-45
-245
11.3
Not an error bar
16O
level scheme
Carbon left in the core
0.8M < M < 25M (from Imbriani et al. 2001).
Core
Collapse
CO
WD
ONeMg
WD
High rate – empty circle
Low rate - Black circle
1 Hp overshoot – triangle
Breathing pulses - square
Supernovae Ia
 Bright
 Homogeneous
 No evolutionary effects
Thermonuclear Explosion
of a CO WD
M~MChandrasekhar
L
~ 1.4 M
Light Curve
56Ni
time

56Co
56 Fe
L  MNi
Roche lobe overflow
H accreting WDs
Single Degenerate system: WD+RG
RG
MS
a) GWR: ang. momentum loss
b) secondary tidal disruption
Merging scenario:
Double Degenerate system: CO+CO
c) accretion 10-5 Myr-1
White Dwarf interior: C and O profiles
High rate
12C(a,g)16O
Low rate
12C(a,n)16O
and the final mass of 56Ni
DM(56Ni)=10%
Rate
HIGH LOW
-19.21
-19.30
Rise time 18.0 d
15.3 d
MV
Observed: 18± 0.4 d
from
Dominguez, Hoflich, Straniero 2002
HIGH Rate C/O 
Massive stars
from Limongi, Chieffi & Straniero
2001
g
e-,e+
g
e-
n,n
n,n
Degenerate
electrons
Thermal
contribution
Pressure contributions
At the onset of the core collapse
< Ye > 0.45  M Ch  1.18
• e-+p  n+ne (10 MeV)
• 56Fe+g  13a+4n (124
MeV)
COLLAPSE, BOUNCE & STALL
1051 erg lost each 0.1 Mo
hard core
(1014 g/cm3)
+0.2 ms
-0.5 ms
+2.0 ms
subsonic | supersonic
1012 g/cm3
3x1014 g/cm3
Ye and 12C(a,g)16O
Low rate
(solid)
High rate
(dotted)
< Ye > 0.45  M Ch  1.18
from Imbriani et al. 2001
M-R relation:
high rate =
shorter C
burning = more
compact
progenitor
Observable consequences: SN yields
1) Intermediate-light elements, Ne, Na, Mg, and Al (which are produced in the C
convective shell), scale directly with the C abundance left by the He burning because
they depend directly on the amount of available fuel.
2) All the elements whose yields are produced by any of the four explosive burnings
(complete explosive Si burning, incomplete explosive Si burning, explosive O burning,
and explosive Ne burning) scale inversely with the C abundance left by the He burning
because the mass-radius relation in the deep interior of a star steepens as the C
abundance reduces.
3) A low C abundance (about 0.2 by mass fraction), or an high rate, is required to
obtain yields with a scaled solar distribution.
5) A low C abundance leads to smaller iron cores, thus favoring the explosion.