NIC12 r-process workshop 04 - 05 August 2012 Are Core-Collapse - PowerPoint PPT Presentation

「重力崩壊型超新星は、（まだ） R過程サイトの天体サイト候補なのか？」 （西村 信哉） NIC12 r-process workshop 04 - 05 August 2012 “Are Core-Collapse Supernovae still possible sites for the r-process?” Nobuya Nishimura

heavy element nucleosynthesis beyond iron RIKEN RIBF Website Solar system abundances neutron → proton → neutron capture s -element r -element p -element ～ 1% by not neutron capture Anders & Grevesse (1989)

Where are the astronomical sites? PNS extremely neutron rich matter mild neutron + high entropy BH formation prompt explosion r-process? r-process? r-process? r-process? BH NS binaries massive stars compact star SN SN merger compact star delayed explosion SN neutrino-driven wind (BH+disk) collapsar models main site?

Newtrino Driven Wind self-consistent simulation of NDW based on NDW’s are proton-rich proton rich rather than neutron-rich state of the art hydrodynamic simulation ( in 1D: spherical symmetry ) Fischer et al. 2010 progenitor: 10.8 M  progenitor: 8.8 M  0.6 0.6 0.5 0.5 e e Electron Fraction, Y Electron Fraction, Y 0.4 0.4 0.3 0.3 0.2 0.2 0.1 0.1 0 0 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 Time After Bounce [s] Time After Bounce [s] e − + p � n + ν e , e + + n � p + ν e , e − + � A , Z � � � A , Z − 1 � + ν e ,

SN simulation & nucleosynthesis • Y e > 0.4 ( 2D model ); weak r-process ( Wanajo 2009, 2011 ) ( Wanajo 2011 ) • successful explosion models ( both 1D and 2D ) • Y e > 0.48 ( Fujimoto et al. 2011 ) • ( ONeMg stars ) SNe • normal SNe via neutrino heating ( > 10M  ) ～8 M  (1D&2D) > 10 M  (2D)( Fujimoto 2011 ) 1 5 Y e, min = 0.466 1D 2D 4 0.1 mass [10 -3 solar] Y e, min = 0.404 3 m/M sun 0.01 2 0.001 1 0 1e-04 0.40 0.45 0.50 0.55 0.46 0.48 0.50 0.52 0.54 Y e Ye (10 , 000 km )

The Core-Collapse Supernova itself is no longer the r-process site? • quark-hadron phase transition → Quark/Hybrid stars • MHD Jet supernova (Strong Mag. fields) → Magnetars both are explosion mechanisms avoiding neutrino heating (= destroy neutrons) extra-scenarios are still certain candidate

Basel GSI Darmstadt F.-K. Thielemann M. Hempel R. Käppeli T. Rauscher C. Winteler “Nucleosynthesis in core-collapse supernova explosions triggered by Quark-Hadron phase transition” Nishimura et al., ApJ in press ( arXiv: 1112.5684 ) collaborators T. Fischer G. Martínez-Pinedo C. Frölich ( North Carolina ) I. Sagert ( Michigan )

CC-SN via quark-hadron phase transition collapse neutron stars or magnetars Quark/Hybrid stars QCD phase transition neutrino or MHD effect energy release from the proto-neutron star standard ( disadvantage to r-proc. )

SNe via the quark-hadron phase transition blue：ν e red : ν e green : ν μ/τ Dasgupta et al. PRD 81 (2010) • EOS：Shen EOS + MIT bag model • GR-hydro. + neutrino transport Sagert et al. (2009)、Fischer et al. (2011) after the normal core-bounce : quark-hadron phase transition occurs 5 1.2 x 10 0.8 Velocity [km/s] 0.4 0 − 0.4 − 0.8 53 erg/s] 53 erg/s] 1 2 3 10 10 10 1 Radius [km] Luminosity [10 1 Luminosity [10 10 5 0 0.255 0.26 0.265 Time after bounce [s] 10 4 0 radius [km] rms Energy [MeV] 30 10 3 25 20 10 2 15 10 1 10 0 0.1 0.2 0.3 0.4 0.5 0 1 2 3 4 Time after bounce [s] time after bounce [s]

the explosion model prompt neutrino driven wind 10 5 10 4 radius [km] 10 3 10 2 10 1 0 1 2 3 4 time after bounce [s]

ejection process & neutron richness (MPA group) neutrino absorption Kitaura et al. 2006 10 5 0.6 0.5 10 4 0.4 radius [km] 10 3 Y e 0.3 0.2 10 2 0.1 10 1 0 0 1 2 3 4 0 1 2 3 4 time after bounce [s] time after bounce [s] ONeMg( 8 M  )

entropy & Y e : the end of NSE ( T = 9 GK ) mass, M # [10 -2 M ⊙ ] 0.209 0.217 1.482 90 0.60 entropy Y e 80 electron fraction, Y e,NSE entropy, s NSE [k B ] 70 0.50 60 NDW delayed prompt 50 0.40 40 30 0.30 20 40 60 80 100 120 mass zone #

the final abundances: total ejecta each zone mass, M # [10 -2 M ⊙ ] 0.209 0.217 1.482 90 0.60 entropy Y e 80 electron fraction, Y e,NSE entropy, s NSE [k B ] 70 0.50 10 2 60 NDW delayed prompt result 50 0.40 solar 40 10 1 30 0.30 20 40 60 80 100 120 abundance mass zone # 10 0 10 -1 NDW -3 delayed abundance, log 10 Y A prompt -4 10 -2 -5 50 70 90 110 130 mass number -6 -7 -8 -9 40 80 120 160 200 mass number, A

final abundances (represented) : each zone neutrino outer “delayed” inner driven wind “prompt” mass number, A 10 50 90 130 10 50 90 130 10 50 90 130 0 0 #015 #017 #019 -1 -1 -2 -2 -3 -3 -4 -4 -5 -5 -6 -6 0 0 #020 #040 #045 -1 -1 -2 -2 abundance, log 10 X A abundance, log 10 X A -3 -3 -4 -4 -5 -5 -6 -6 0 0 #050 #051 #060 -1 -1 -2 -2 -3 -3 -4 -4 -5 -5 -6 -6 0 0 #070 #080 #120 -1 -1 -2 -2 -3 -3 -4 -4 -5 -5 -6 -6 10 50 90 130 10 50 90 130 10 50 90 130 mass number, A

final abundances: neutrino driven winds A < 85 elements are produced via νp-process ν p-proc. without overproduction, log 10 X/X ⊙ 3 2 1 0 30 40 50 60 70 80 90 mass number, A

over 10% reductions are becoming physical uncertainties: Y e unphysical for current model 1 + p cor � � Y e , cor = 0 . 5 + ( Y e − 0 . 5) × 100 electron fraction, Y e electron fraction, Y e 0.20 0.30 0.40 0.50 0.20 0.30 0.40 0.50 0 0 Y e (standard) Y e - 10% mass fraction mass fraction -1 -1 -2 -2 -3 -3 Y e - 20% Y e - 30% mass fraction mass fraction -1 -1 -2 -2 -3 -3 0.20 0.30 0.40 0.50 0.20 0.30 0.40 0.50 electron fraction, Y e electron fraction, Y e

Y e uncertainties with observation Metal poor stars ( weak r-process ) solar system ( strong r-process ) 40 80 120 160 200 -2 standard p cor = 10 p cor = 30 p cor = 40 -3 solar abundance, log 10 Y A -4 -5 -6 standard 0 p cor = 10 p cor = 30 -7 p cor = 40 abundance, log 10 Y Z -1 HD122563 NDW -2 -3 delayed abundance, log 10 Y A prompt -4 -3 -5 -4 -6 -7 -5 -8 30 40 50 60 70 80 atomic number, Z -9 40 80 120 160 200 mass number, A

conclusion → need different model ( multi-D, progenitor, EoS etc. ) • r-process nucleosynthesis • reproduce A～110 r-element ( “weak” r-process ) • 2 nd peak is the limit within the physical uncertainty • “strong” r-process require 30% decrease of Y e ‘s • neutrino driven wind • similar environment to normal CC-SNe • A ～ 90 proton-rich isotopes ( νp-process )

Jet-like SN induced by Magnetic fields jet/hypernova image mag. field B ～ 10 15 G • neutron stars have strong magnetic fields Zhang (2000) APJL • Hypernovae • GRB central engine • Jet-like Explosions • magnetar : ～ 10 15 G ( ～ 1 % of the neutron stars ) • neutron stars ( pulsars ) : ～ 10 12 G 16 14 12 -1 0 1

MHD “Jet” supernova explosion : • 2D Newtonian without neutrino • MHD-SN: Nishimura et al. 2006 • “Collapsar model” ( BH + disk ): Fujimoto et al. ( 2007, 2008 ) • 2D Relativity and neutrino cooling: - explosion model: Takiwaki et al. 2009 - nucleosynthesis: Nishimura et al. (2010, 2012 prep ) Nishimura 2010 Takiwaki 2009

Winteler et al. ApJL 2012; ( Basel collaboration ) The first r-proc. study based on 3D MHD models green : no neutrino red : includes neutrino M ej = 0.672 x 10 -2 M  10 − 2 Ejected Mass [M � ] 10 − 3 10 − 4 10 − 5 10 − 6 10 − 7 60 80 100 120 140 160 180 200 220 240 Mass Number

The first r-proc. study based on 3D MHD models • long-term simulations • systematic survey of wide range of mag. and rot. • weak initial mag. field rot. • detailed micro-physics (neutrino, EOS and mag. fields, etc.) • detailed macro-physics (magneto-rotational instabilities) • relation to (optical) observation • large breaking of axis-symmetry • different rotational and mag. axis ... • ... In the context of r-proc. study (and also explosion mechanism), there are still a lot of open questions. long-term simulations based on wider range of initial conditions under axis-symmetry. (2D hydro. with rot. and mag. fields)

MHD “Jet” supernova explosion : Nishimura at al. (2012 prep.) based on MHD-SN model by Takiwaki 2009 ejected r-elem. mass ( typically ) M r-elem. ～ 10 -3 to 10 -2 M  movie