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Nucleosynthesis of Light Elements Through the Ν-Process in Supernova

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Nucleosynthesis of Light Elements Through the Ν-Process in Supernova Nucleosynthesis of Light Elements through the n-Process in Supernova Explosions Takashi YOSHIDA Astronomical Institute, Tohoku University Toshitaka KAJINO National Astronomical Observatory of Japan Department of Astronomy, University of Tokyo in NIC7 (2002) Supernova Theory And Nucleosynthesis, July 17, Seattle The n-Process Huge amount of neutrinos from proto-neutron star interact with nuclei in exploding material The n-process Li, B (Light elements): Woosley et al. (1990), Woosley & Weaver (1995) Rauscher et al. (2002), Heger et al. (2003), Yoshida et al. (2004) 19F, 15N: Woosley et al. (1990), Woosley & Weaver (1995) Rauscher et al. (2002), Heger et al. (2003) 138La, 180Ta: Goriely et al. (2001), Rauscher et al. (2002) Heger et al. (2003) The r-process: Meyer et al. (1992), Woosley et al. (1994) Takahashi & Janka (1994), Hoffman et al. (1997) NS Otsuki et al. (2000), Terasawa et al. (2002, 2004) etc. etc... Overproduction of 11B in SNe Galactic chemical evolution (GCE) of B 10B Galactic Cosmic Rays (GCRs) 11B GCRs, Supernovae Supernova contribution of 11B amount in the GCE to reproduce 11B/10B at the solar metallicity 11 11 11 11 11 B = B(GCR)+ B(SN) = B + B(SN) 10B 10B(GCR) 10B GCR 10B(GCR) GCE =4.05 (primitive meteorites) ~2.5 ~1.5 11B amount from supernova nucleosynthesis model (WW95) 11B(SN) 11B(SN) = 2.5~5.6 10B(GCR) Model 10B(GCR) GCE Overproduction of 11B in supernovae Purpose of the Present Study 11B and 7Li amounts produced through the n-process depend on the characteristics of the supernova neutrinos NOT determined uniquely strongly connected to supernova explosion mechanism Purpose of the present study Investigate dependence 11 7 B and Li masses Supernova neutrino parameters Tnm,t: temperature of nm,t and nm,t En : total neutrino energy Constraint on supernova neutrinos from GCE of 11B resolve the overproduction problem of 11B in GCE Supernova Model Supernova neutrinos 1 En t-r/c Luminosity L (t)= exp - Q(t-r/c) ni : nemt,nemt tn=3 s ni 6 tn ( tn ) (Woosley et al. 1990, WW95) Energy spectra Fermi distribution (mn=0) Tne=3.2 MeV, Tne=5.0 MeV Parameters Total neutrino energy Temperature of nm,t and nm,t En : 100 foe < En < 600 foe Tnm,t : 4 MeV < Tnm,t < 9 MeV Supernova explosion model 16.2 M presupernova corresponding to SN 1987A (Shigeyama & Nomoto, 1990) Spherically symmetric Lagrangian PPM code (Shigeyama et al. 1992) Explosion energy: 1 foe, Mass cut: 1.61 M Nuclear reaction network 291 species of nuclei n-process rates Hoffman & Woosley (1992) Abundance Distribution of Light Elements Inner O/C He/C He/N H 14 10-6 11B N 7Li (n,n'n) 11 12 C C (a,n) Fraction 10-9 (a,g) 10B (b+) (n,n'p) 7 11 9 Be B Mass Be (e-,ne) ( , ) 6Li a g 10-12 (a,g) 2 3 4 5 6 7 8 9 3He 4He 7Li Mr / M (n,n'n) 16.2 M star SN (n,n'p) (a,g) 3 En=300 foe, Tnm,t=6 MeV, tn=3 s H 7Li & 11B production in He/C layer 4He(n,n’p)3H, 4He(n,n’n)3He, 12C(n,n’p)11B Neutrino Parameter Dependence on 11B 4 10-6 4 10-6 600 tn=3 s 3 10-6 3 10-6 ⊙ ⊙ t =1 s M T =8 MeV n M / nm,t / ) 2 10-6 ) 2 10-6 B B WW95 WW95 11 =9 s 11 ( tn ( M 1 10-6 3 s M 1 10-6 1 s 300 Tnm,t=6 MeV 0 0 En=100 foe 1 2 3 4 5 6 4 5 6 7 8 9 53 En (¥10 ergs) Tnm,t (MeV/k) (Yoshida et al. 2004) 11B ejected mass roughly proportional to En Tnm,t dependence is stronger than En dependence GCE of 11B and Supernova Neutrinos -6 4 10 11 600 Evaluation of B mass in ~20M star SN ejecta from GCE models 3 10-6 ⊙ (Fields et al. 2000, Ramaty et al. 2000, M 350 / Ramaty, Lingenfelter, & Kozlovsky 2000, ) 2 10-6 Alibes, Labay, & Canal 2002) B WW95 11 -7 11 -7 ( 240 3.33´10 M < M( B) <7.4´10 M M -6 11 -6 1 10 300 (M( B) = 1.85´10 M ,WW95) En ~ Gravitational energy of E =100 foe 0 n a ~1.4 M neutron star 4 5 6 7 8 9 (Lattimer & Prakash 2001) Tnm,t (MeV/k) 240 foe < En < 350 foe 11 Constraint on Tnm,t range from M( B) in GCE and En 4.8 MeV < Tnm,t < 6.6 MeV Lower neutrino temperature is favorable! Conclusions We investigated the dependence of the supernova neutrino parameters such as Tnm,t and En on the light element synthesis using a supernova explosion model of 16.2 M star. 7Li & 11B production in He/C layer 4He(n,n’p)3H, 4He(n,n’n)3He, 12C(n,n’p)11B 11B ejected mass roughly proportional to En Tnm,t dependence is stronger than En dependence 11 Constraint on Tnm,t range from M( B) in GCE and En 4.8 MeV < Tnm,t < 6.6 MeV Lower neutrino temperature is favorable!.
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