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Nucleosynthesis in Pop III, Nucleosynthesis in Pop III, Massive and Low-Mass StarsMassive and Low-Mass Stars
Nobuyuki Iwamoto Nobuyuki Iwamoto (( Univ. of TokyoUniv. of Tokyo ))withwith
H. Umeda, & K. NomotoH. Umeda, & K. Nomoto
• Extremely metal-poor (EMP) stars ([Fe/H]<–2.5) may have abuExtremely metal-poor (EMP) stars ([Fe/H]<–2.5) may have abundance patterns created by Pop. III supernovae (SNe). ndance patterns created by Pop. III supernovae (SNe).
• Surface chemical compositions observed in the most Fe-poor Surface chemical compositions observed in the most Fe-poor star star HE0107-5240HE0107-5240 are thought to be attributed to are thought to be attributed to
– single supernovae with M>~20-130Msingle supernovae with M>~20-130M (Umeda & Nomoto 2 (Umeda & Nomoto 2003)003)
– two (or more) supernovae with SNe of low mass and massitwo (or more) supernovae with SNe of low mass and massive black-hole forming SNe (Limongi, Chieffi, & Bonifacio 20ve black-hole forming SNe (Limongi, Chieffi, & Bonifacio 2003)03)
• Evolution of the observed low-mass star may be important. Evolution of the observed low-mass star may be important.
Mn
Co
Cr
Zn
trend
McWilliam, Ryan, Spite,
[Fe/H][Fe/H]
Ia
Ic
Ib
94I
97ef
98bw
HeCaO
SiII
Hyper -novae
Spectra of Supernovae & HypernovaeSpectra of Supernovae & Hypernovae
HypernovaeHypernovae:: broad
features blended lines “ Large mass
at high velocities”
IcIc: no H, no strong He, no strong Si
84L
94D
more
mass
ive
more energetic explosion
0 50 100 t (days)
98bw&CO138
97ef&CO100
Radioactive Decay 56Ni 56Co 56Fe
C+O Star ModelsC+O Star Models
98bw98bw 97ef97ef 94I94I
MMmsms
(M(M))
4040 3535 1515
MMC+OC+O
(M(M))
13.813.8 10.010.0 2.12.1
EEKK
(10(105151erg)erg)
3030 2020 11
M(M(5656Ni)Ni)(M(M))
0.50.5 0.150.15 0.070.07
log L (erg/s)
43
42
41
Light curves of Hypernovae & SNe IcLight curves of Hypernovae & SNe Ic
94I&CO21
Normal SNe Hypernovae
(1) M(Complete Si-burning)
(Zn, Co)/Fe
(Mn, Cr)/Fe
Fe/(O, Si)
(2) More ‐rich entropy
Zn/Fe 64Ge
(Ti, Ni)/Fe
(3) More O burns
(Si, S, Ca)/O
Hypernova NucleosynthesisHypernova Nucleosynthesis
Normal SNe and hypernovaeNormal SNe and hypernovae
• thanthan
-rich freeze-out
enhancement of elements heavier than Fe (Co and Zn)
Umeda et al. 2002Normal SNe Hypernovae
For the same mass cut, mass ratio of complete Si burning region to incompleteSi burning region becomes larger.
complete Siburning
incomplete Siburning
15M, E51=1
25M, E51=30(Hypernova)
Mn
Co
Cr
Zn
Umeda & Nomoto 2003
Carbon-rich EMP StarsCarbon-rich EMP Stars
Aoki et al. (2002)
-4 -3 -2 -1 0[Fe/H]
[C/F
e]
2
1
0
-1
C-Rich, Extremely Metal-Poor Star: C-Rich, Extremely Metal-Poor Star: CS22949-037 ([Fe/H]=– 4.0)CS22949-037 ([Fe/H]=– 4.0)
30M30M, E=2, E=2××10105252ergerg [Zn/Fe] [Zn/Fe] ~ +~ +0.70.7 Zn,Co enhancementZn,Co enhancementM(M(5656Ni)Ni)~~33××1010-3-3MM, M(BH), M(BH)~8M~8M
Norris et al. Dapagne et al.
Energetic but relatively faint supernova
C-rich, EMP stars may be formed by black-hole forming SNe.
Mixing and FallbackMixing and Fallback
ejectaFallback
MBH ~ 6M
Umeda & Nomoto (2003)Mixing
M=25MM=25M, E=3, E=3××10105050ergerg
The Most Iron-Poor Star: HE0107-5240The Most Iron-Poor Star: HE0107-5240 (Chriest(Chriestlieb et al. 2002)lieb et al. 2002)
[Fe/H] = - 5.3[C/Fe] = +4.0 [N/Fe] = +2.3[Na/Fe] = +0.8
[Mg/Fe] = +0.2 [Ca/Fe] = +0.4 [Ti/Fe] = - 0.4 [Ni/Fe] = - 0.4
no s- & r- enhancement : no companion starM = 25M E = 3×1050ergsMHe = 8M C+N from He layerMCO = 6M MBH
M(Fe) ~ 10-5M
Umeda & Nomoto (2003) Nature, 422, 871
12C/13C>30
Standard evolution of a 0.85MStandard evolution of a 0.85M star star
HE0107-5240He core H-richEnvelope
ignition of He burning
Mc/M
=0.25
0.3
0.35
0.4
0.45
0.486
Initial composition: yield of Pop. III 25M supernova with explosion energy E=0.3x1051 erg (Umeda & Nomoto 2003)
Elemental AbundancesElemental Abundances
HE0107-5240
after the first dredge-up in the standard evolution
initial composition
Evolutionary Track of a 0.85MEvolutionary Track of a 0.85M star with star with mixing between H burning shell and He mixing between H burning shell and He corecore
onset of proton mixing
He core
H-rich envelopeconvective
radiative
He core
H-rich envelopeconvective
radiative
He core
H-rich envelope
convective
convective
~ 5x107 yr/~108 yr (lifetime on the RGB)
dredge-up
Variation of Abundance Variation of Abundance Distributions after Proton MixingDistributions after Proton Mixing
14N16O
12C 13C
23Na22Ne
20Ne
19F
after 3900yr
after 10000yr
Xp=10-2
D=106cm2/sec
19F
22Ne23Na
20Ne
12C14N16O
13C
1H
Elemental AbundancesElemental Abundances
HE0107-5240
after the first dredge-up in the standard evolution
after proton mixing
initial composition
12C/13C = 43.5
Results of Limongi et al. 2003Results of Limongi et al. 2003
• Fluorine might be important to understand the Fluorine might be important to understand the origin of HE0107-5240.origin of HE0107-5240.
[F/Fe]~2.7
Summary: First Supernovae and EMP Summary: First Supernovae and EMP starsstars
• EMP Stars: [Fe/H] < EMP Stars: [Fe/H] < -- 2.52.5– Trends in [(Zn, Co, Mn, Cr)/Fe]Trends in [(Zn, Co, Mn, Cr)/Fe]– CN-rich StarsCN-rich Stars– HE0107-5240 (Christlieb et al.)HE0107-5240 (Christlieb et al.)– Na (F & Al) production Na (F & Al) production by the proposed internal processby the proposed internal process
• Black-Hole Forming SupernovaeBlack-Hole Forming Supernovae Variations in Variations in
Explosion Energy RotationExplosion Energy Rotation Mixing & Fallback BinarityMixing & Fallback Binarity Jets, …Jets, …
High Energy, Jets
Mixing and Fallback
(~20M–130M)
Na/O anti-correlation in globular cluster