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