1 / 19

Nucleosynthesis in Pop III, Massive and Low-Mass Stars

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]<–2.5) may have abundance patterns created by Pop. III supernovae (SNe).

indigo-cherry
Download Presentation

Nucleosynthesis in Pop III, Massive and Low-Mass Stars

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

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

  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.

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

  4. 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 97ef Hyper-novae 98bw more energetic explosion

  5. Light curves of Hypernovae & SNe Ic log L (erg/s) Radioactive Decay 56Ni 56Co 56Fe 43 98bw&CO138 42 97ef&CO100 41 94I&CO21 0 50 100 t (days)

  6. 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 Hypernovae Normal SNe

  7. Normal SNe and hypernovae Hypernovae Normal SNe Umeda et al. 2002 • than complete Si burning incomplete Si burning 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

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

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

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

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

  12. The Most Iron-Poor Star: HE0107-5240(Chriestlieb et al. 2002) Umeda & Nomoto (2003) Nature, 422, 871 [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 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

  13. 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

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

  15. Evolutionary Track of a 0.85M8star with mixing between H burning shell and He core ~ 5x107 yr/~108 yr (lifetime on the RGB) H-rich envelope H-rich envelope convective convective radiative radiative convective He core He core onset of proton mixing H-rich envelope convective dredge-up He core

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

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

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

  19. Summary: First Supernovae and EMP stars High Energy, Jets • 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, … Mixing and Fallback Na/O anti-correlation in globular cluster (~20M–130M)

More Related