E M M I work s hop @GSI 07 / 16 / 2010 R-process Nucleosynthesis in Magnetically dominated Core-Collapse Supernovae NISHIMURA, Nobuya （西村 信哉） National Astronomical Observatory of Japan Collaborator s Tomoya Takiwaki (NA OJ / CfC A) Ma s a-aki Ha s himoto (Kyu s hu Univ . ) Kat s uhiko Sato (IPMU / M e i s e i Univ . )
Outline � Introduction � MHD SN as an astronomical r-process site � Explosion models and nucleosynthesis � MHD Supernova model � Tracer particle motion and Ye evolution � r -process nucleosynthesis � Summary
Massive star and supernova (SN) explosion � Ma ss iv e s tar s (M / M � � 10) in c ud e Gravitational c ollap s e � Onion-lik e lay e r s (H � H e � O / C � N e / O � Si � F e ) � Explo s iv e e nd & Compa c t obj ec t � Sup e rnova e and N e utron s tar s � Bla c k Hol e s , J e t s � long GRB s , Hyp e rnova e Collap s e Boun ce Explo s ion
r-process and core-collapse supernova � Neutrino-Driven Explosion models � SASI (Iwakami et al. 2008, etc.) � canonical Supernova mechanism? � Proton-rich matter? (neutrino interaction) � Neutrino Driven Wind (from Proto-Neutron star) high-enthropy model � Magneto-hydrocynamic Explosion models � MHD effect (Takiwaki et al. 2009, etc.) � origin of Magnetars and GRBs ? � Neutron rich matter � a large amount of ejection mass
the condition of the 3 rd peak elements t e xp : tim e s c al e of e xpan s ion rapidly w e ak n e utrino e ff ec t int e rmadiat e s low s trong n e utrino e ff ec t 3 rd p e ak M HD-SN ? Hoffman , Woo s l e y , and Qian (1997)
Astrophysical Site Solar s y s t e m r- e l e m e nt （ 10 -7 M � ） : log10(Ma ss ) Sit e s r- e l e m e nt ma ss Ev e nt rat e e ntropy Y e (log10 M � ) (log10[ / y e ar / gal]) N e utrino Driv e n high high ? -5 -2 （＞ 100 ） （～ 0 . 3 ） Wind (NDW) N e utron Star binary Low Low ? -2 -5 （～ 0 . 1 ） M e rg e r M HD Sup e rnova 10 -2 ? 10 -5 ？ （～ 0 . 1 ） Low Collap s ar Mod e l V e ry high log -2 ? -5 (M HD) Woo s l e y e t al . 1996 , Hoffman e t al . 1997 , Wanajo e t al . 2001 , Fr e iburghau s e t al . 1999 , Sumiyo s hi e t al . 2000 , Fujimoto e t al . 2007
R-process nucleosynthesis in a MHD jet model A s trophy s i c al mod e l s for Nu c l e o s ynth e s i s s tudi e s � Hydrodynami c Cal c ulation s for SN e Magn e to-hydrodynami c mod e l � J e t-lik e Sup e rnova Explo s ion W e u s e th e M HD J e t mod e l s h e r e . � Bla c k hol e j e t s (Collap s ar mod e l s ) Fujimoto e t al . (2007) Fujimoto , NN , Ha s himoto (2008)
MHD Jet SN and MHD Collapsar Model final s tag e of St e llar e volution Suparnova Neutron star M ＜ 25M � NS SN j e t a cc r e tion di s k M ＞ 25M � c ollap s e Bla c k Hol e Th e ce ntral e ngin e of GRB s
R-process for MHD Collapsar Model M HD driv e n J e t from Collap s ar mod e l Fujimoto , NN , Ha s himoto (2008) M HD Collap s ar mod e l � Strong magn e ti c fi e ld s and rapidly rotation � N e wtonian M HD � No n e utrino e ff ec t (dynami c s and r-pro ce ss )
Previous work: r-process in MHD SN � MHD Supernova Explosion model � 13M � (main sequence) pre-collapse model � r-processes occur in two models (strong magnetic fields and rapidly rotation) N e utrino e ff ec t s Nishimura et al. (2006)
Problems of previous work M HD Explo s ion mod e l � Newtonian MHD simulation SR-M HD Mod e l � No neutrino effect for dynamics (no cooling and heating) L e akag e S c h e m e Nu c l e o s ynth e s i s � Weak Interaction + inv e r s e r e a c tion by n e utrino (electron and positron capture) + the number of Tracer Particles is NOT enough. W e improv e s om e phy s i c al pro ce ss .
Special Relativistic MHD explosion models SR M HD + N e utrino c ooling (Takiwaki + 2009) Magn e ti c Fi e ld Lin e Str e amlin e s
Initial models for MHD simulation St e llar D e n s ity , En e rgy and Y e di s tribution s ar e adopt e d from pr e - c ollap s e mod e l s (25M � : H e g e r e t al . 2000) differential rotation Poloidal magnetic field Angular v e lo c ity � Sid e vi e w 100km 2000km 1000km
MHD Supernova Explosion models W e fo c u s on th e s hort e s t tim e s c al e and mo s t e n e rg e ti c mod e l s . B12T W1 . 0 (Takiwaki e t al . 2009) B11TW1.0 B12TW1.0 Thi s work th e s ho c k-arrival tim e to th e radiu s of 1000 km aft e r boun ce
T12TW1.0: hydrodynamic evolution T12T W1 . 0: R e d (Takiwaki e t al . 2009) Toroidal magn e ti c fi e ld L e ft: Right: �������������������� Poloidal magn e ti c fi e ld
Tracer Particle: setting & motion r-dir ec tion: 1000 � -dir ec tion: 500 Total: 500 , 000 e j ec t e d: ～ 6 , 000 F e c or e (1000km)
r-process: physical condition ① Neutronization ( T > 0.5MeV) ： Ye � � NSE(Nuclear Statistical Equilibrium) state electron capture (p + e - �� n + � e ) ： Core-Collapse � (reverse reaction （ ����� e � p + e - ）： neutrino heating) ② Seed creation ( T > 0.2MeV) ： mass number ～ 100 � � -process (4He) ③ R-process ( �������� - - decay � Y e ： e l ec tron fra c tion � ������ (high temperature) p � Y e ④ decay � n p � - - decay � Low Y e ＝ Low p ＝ n e utron-ri c h � fission (heavy element)
Abundance Evolution ( T � 10 [GK] ) � Abundance � Nuclear Statistical Equilibrium � Partition Function (REACLIB) � Reaction � only weak process � reaction rate (FFN 1985) Y e : tim e e volution Qian & Woo s l e y (1996)
Effects Proto-Neutron Star (neutrino burst) 1000 [km] Radiu s of th e n e utrino s ph e r e � e : ー � e : ー � x : ー 100km 100 [km] N e utrino Shp e r e
Physical quantities of neutrino sphere R � � R � : radiu s of n e utrino s ph e r e � <E � > : m e an e n e rgy � L � : lumino s ity � e : ー � e : ー � x : ー <E � > L �
Ye evolution and neutrino effect Y e e volution N e utrino Bur s t
Ye distribution no n e utrino (only e l ec tron + po s itron c aptur e ) Th e di s tribution s lant to th e right . Valu e s of Y e ar e in c r e a s e d about 0 . 1 . n e utrino e ff ec t 0 . 1 0 . 2 0 . 0 0 . 3 0 . 4 0 . 5
Density and Temperature: Ye ～ 0.1 T e mp e ratur e D e n s ity (log [K]) (log [g / cc ]) 10^11[K] Prompt Explo s ion M HD SN (13M � ) Sumiyo s hi+ 2001 10^11[K] Ni s himura+ 2006
r-process: physical condition ① Neutronization ( T > 0.5MeV) ： Ye � � NSE(Nuclear Statistical Equilibrium) state electron capture (p + e - �� n + � e ) ： Core-Collapse � (reverse reaction （ ����� e � p + e - ）： neutrino heating) ② Seed creation ( T > 0.2MeV) ： mass number ～ 100 � � -process (4He) ③ R-process ( �������� - - decay � Y e ： e l ec tron fra c tion � ������ (high temperature) p � Y e ④ decay � n p � - - decay � Low Y e ＝ Low p ＝ n e utron-ri c h � fission (heavy element)
Nuclear Reaction Network Numb e r fra c tion Y i for i th e l e m e nt thr ee -body d ec ay two-body FRDM N e twork r-pro ce ss � 4071 isotopes � Reaction rates ： REACLIB � � -decay ： theory FRDM mass formula Nuclear chart Nuclear chart
r-element abundances Th e r e s ult of n e twork s imulation . Di s tribution r-pro ce ss e l e m e nt s c ompar e d with s olar r- e l e m e nt di s tribution . a v e rti c al axi s : normaliz e d ma ss fra c tion n e utrino e ff ec t
After the Jet: Wind like state � R- e l e m e nt 0 . 83E-2 (0 . 0083) M � � Oth e r e l e m e nt 4 . 32E-2 (0 . 0432)M � � Flow n e ar th e ce nt e r 2 . 3 e -4M � [ / s ec ond] Low r e s olution (ov e r e s timat e ) NO T N e utrino Driv e n Wind (M HD pro ce ss )
Astrophysical Site Solar s y s t e m r- e l e m e nt （ 10 -7 M � ） : log10(Ma ss ) Sit e s r- e l e m e nt Ev e nt e ntropy Y e ma ss (1 / y e ar / gal) (M � ) N e utrino Driv e n V e ry high high ? -5 -2 （～ 100 ） （～ 0 . 4 ） Wind (NDW) N e utron Star binary low Low ? -2 -5 Magn e tar s （～ 0 . 1 ） M e rg e r （～ 0 . 1 ） M HD Sup e rnova low -2 ? -5 Collap s ar Mod e l V e ry high Low -2 ? -5 (M HD) Coll s par Mod e l V e ry high? High? ? ? (ND J e t or outflow) GRB s
Summary M HD Sup e rnova Explo s ion mod e l s � Sp ec ial R e lativi s ti c M HD � N e utrino c ooling � NSE abundance evolution � more neutron rich matter � Ye is changed by neutrino effect( ～ +0.1) � Heavy elements � r-element mass: 0.83E-2 (0.0083) M � � Mass of 56Ni : 0.024 M � (Faint SN?)
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