Nucleosynthesis in Pop III, Massive and Low-Mass Stars Nobuyuki Iwamoto （Univ. of Tokyo） with H. Umeda, & K. Nomoto

Extremely metal-poor (EMP) stars ([Fe/H]<–2 Extremely metal-poor (EMP) stars ([Fe/H]<–2.5) may have abundance patterns created by Pop. III supernovae (SNe). Surface chemical compositions observed in the most Fe-poor star HE0107-5240 are thought to be attributed to single supernovae with M>~20-130M8 (Umeda & Nomoto 2003) two (or more) supernovae with SNe of low mass and massive black-hole forming SNe (Limongi, Chieffi, & Bonifacio 2003) Evolution of the observed low-mass star may be important.

McWilliam, Ryan, Spite, Cr Mn trend Co Zn [Fe/H] [Fe/H]

Spectra of Supernovae & Hypernovae 94D Ic: no H, no strong He, no strong Si SiII Ia O Ca He 84L Ib Hypernovae： 　　broad features 　　blended lines 　　“Large mass at high velocities” more massive Ic 94I Hyper　　-novae 97ef 98bw more energetic explosion

Light curves of Hypernovae & SNe Ic log L (erg/s) Radioactive Decay 56Ni 56Co 56Fe C+O Star Models 98bw 97ef 94I Mms (M) 40 35 15 MC+O 13.8 10.0 2.1 EK (1051erg) 30 20 1 M(56Ni) 0.5 0.15 0.07 43 98bw&CO138 42 97ef&CO100 41 94I&CO21 0 50 100 t (days)

Hypernova Nucleosynthesis (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 Normal SNe Hypernovae

Normal SNe and hypernovae Umeda et al. 2002 complete Si burning incomplete Si burning than enhancement of elements heavier than Fe (Co and Zn) For the same mass cut, mass ratio of complete Si burning region to incomplete Si burning region becomes larger. a-rich freeze-out

Umeda & Nomoto 2003 Cr 15M, E51=1 Mn 25M, E51=30 (Hypernova) Co Zn

Carbon-rich EMP Stars 2 1 [C/Fe] -1 -4 -3 -2 -1 0 [Fe/H] -1 -4 -3 -2 -1 0 [Fe/H] Aoki et al. (2002)

C-Rich, Extremely Metal-Poor Star: CS22949-037 ([Fe/H]=– 4.0) 30M, E=2×1052erg [Zn/Fe] ~ +0.7 Zn,Co enhancement M(56Ni)~3×10-3M, M(BH)~8M Energetic but relatively faint supernova Norris et al. Dapagne et al. C-rich, EMP stars may be formed by black-hole forming SNe.

Mixing and Fallback MBH ~ 6M Mixing ejecta Fallback M=25M, E=3×1050erg Umeda & Nomoto (2003) Mixing MBH ~ 6M ejecta Fallback

The Most Iron-Poor Star: HE0107-5240 (Chriestlieb 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 Umeda & Nomoto (2003) Nature, 422, 871 12C/13C>30 no s- & r- enhancement : no companion star M = 25M E = 3×1050ergs MHe = 8M C+N from He layer MCO = 6M MBH M(Fe) ~ 10-5M

Standard evolution of a 0.85M8 star Initial composition: yield of Pop. III 25M8 supernova with explosion energy E=0.3x1051 erg (Umeda & Nomoto 2003) 0.486 ignition of He burning 0.45 0.4 0.35 H-rich Envelope He core HE0107-5240 0.3 Mc/M8 =0.25

Elemental Abundances HE0107-5240 initial composition after the first dredge-up in the standard evolution

Evolutionary Track of a 0 Evolutionary Track of a 0.85M8 star with mixing between H burning shell and He core H-rich envelope H-rich envelope ~ 5x107 yr/~108 yr (lifetime on the RGB) convective convective radiative radiative convective He core He core onset of proton mixing H-rich envelope convective dredge-up He core

Variation of Abundance Distributions after Proton Mixing 20Ne 23Na 1H 22Ne 19F 12C 16O after 3900yr 14N 13C Xp=10-2 D=106cm2/sec 20Ne 22Ne 23Na 19F after 10000yr

Elemental Abundances 12C/13C = 43.5 HE0107-5240 initial composition after the first dredge-up in the standard evolution after proton mixing 12C/13C = 43.5

Results of Limongi et al. 2003 [F/Fe]~2.7 Fluorine might be important to understand the origin of HE0107-5240.

Summary: First Supernovae and EMP stars EMP Stars: [Fe/H] < －2.5 Trends in [(Zn, Co, Mn, Cr)/Fe] CN-rich Stars HE0107-5240 (Christlieb et al.) Na (F & Al) production by the proposed internal process Black-Hole Forming Supernovae Variations in Explosion Energy Rotation Mixing & Fallback Binarity Jets, … High Energy, Jets Mixing and Fallback Na/O anti-correlation in globular cluster (~20M–130M)