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

“Are Core-Collapse Supernovae still possible sites for the r-process?”

「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？」

NIC12 r-process workshop 04 - 05 August 2012

Nobuya Nishimura （西村 信哉）

Anders & Grevesse (1989) s-element r-element

p-element neutron capture

～ 1% by not neutron capture

RIKEN RIBF Website

heavy element nucleosynthesis beyond iron

Solar system abundances neutron → proton →

Where are the astronomical sites?

massive stars collapsar models (BH+disk) neutrino-driven wind SN

delayed explosion

compact star merger SN SN compact star binaries PNS NS BH r-process? r-process? r-process? r-process?

prompt explosion BH formation

mild neutron + high entropy extremely neutron rich matter

main site?

Newtrino Driven Wind

self-consistent simulation of NDW based on state of the art hydrodynamic simulation ( in 1D: spherical symmetry ) Fischer et al. 2010

1 2 3 4 5 6 7 8 9 10 0.1 0.2 0.3 0.4 0.5 0.6 Time After Bounce [s] Electron Fraction, Y

e

1 2 3 4 0.1 0.2 0.3 0.4 0.5 0.6 Time After Bounce [s] Electron Fraction, Y

e

e− + p n + νe, e+ + n p + νe, e− + A, Z A, Z − 1 + νe,

progenitor: 10.8 M progenitor: 8.8 M

proton rich NDW’s are proton-rich rather than neutron-rich

SN simulation & nucleosynthesis

• normal SNe via neutrino heating ( > 10M )
• Ye > 0.48 ( Fujimoto et al. 2011 )
• ( ONeMg stars ) SNe
• successful explosion models ( both 1D and 2D )
• Ye > 0.4 ( 2D model ); weak r-process

( Wanajo 2009, 2011 )

Ye mass [10-3 solar] 0.40 0.45 0.50 0.55 1 2 3 4 5 2D Ye, min = 0.404 1D Ye, min = 0.466

1e-04 0.001 0.01 0.1 1 0.46 0.48 0.50 0.52 0.54

m/Msun Ye (10,000km)

> 10 M (2D)( Fujimoto 2011 ) ～8 M (1D&2D)

( Wanajo 2011 )

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

• r

magnetars

Quark/Hybrid stars

QCD phase transition

neutrino

• r

MHD effect

energy release from the proto-neutron star

standard ( disadvantage to r-proc. )

SNe via the quark-hadron phase transition

10

1

10

2

10

3

−0.8 −0.4 0.4 0.8 1.2 x 10

5

Radius [km] Velocity [km/s]

quark-hadron phase transition occurs after the normal core-bounce : Sagert et al. (2009)、Fischer et al. (2011)

• GR-hydro. + neutrino transport
• EOS：Shen EOS + MIT bag model

Dasgupta et al. PRD 81 (2010)

0.1 0.2 0.3 0.4 0.5 Time after bounce [s] 10 15 20 25 30 rms Energy [MeV] 1 Luminosity [10

53 erg/s]

0.255 0.26 0.265

Time after bounce [s]

1

Luminosity [10

53 erg/s]

blue：νe red : νe green : νμ/τ

101 102 103 104 105 1 2 3 4 radius [km] time after bounce [s]

the explosion model

101 102 103 104 105 1 2 3 4 radius [km] time after bounce [s]

prompt neutrino driven wind

ejection process & neutron richness

ONeMg( 8 M)

Kitaura et al. 2006 (MPA group)

101 102 103 104 105 1 2 3 4 radius [km] time after bounce [s] 0.1 0.2 0.3 0.4 0.5 0.6 1 2 3 4 Ye time after bounce [s]

neutrino absorption

entropy & Ye : the end of NSE ( T = 9 GK )

30 40 50 60 70 80 90 20 40 60 80 100 120 0.30 0.40 0.50 0.60 0.209 0.217 1.482 entropy, sNSE [kB] electron fraction, Ye,NSE mass zone # mass, M# [10-2 M⊙] NDW delayed prompt entropy Ye

the final abundances:

10-2 10-1 100 101 102 50 70 90 110 130 abundance mass number result solar

• 9
• 8
• 7
• 6
• 5
• 4
• 3

40 80 120 160 200 abundance, log10 YA mass number, A NDW delayed prompt

total ejecta each zone

30 40 50 60 70 80 90 20 40 60 80 100 120 0.30 0.40 0.50 0.60 0.209 0.217 1.482 entropy, sNSE [kB] electron fraction, Ye,NSE mass zone # mass, M# [10-2 M⊙] NDW delayed prompt entropy Ye

final abundances (represented) : each zone

• 6
• 5
• 4
• 3
• 2
• 1

10 50 90 130 #015 mass number, A mass number, A abundance, log10 XA abundance, log10 XA 10 50 90 130 #017

• 6
• 5
• 4
• 3
• 2
• 1

10 50 90 130 #019

• 6
• 5
• 4
• 3
• 2
• 1

#020 #040

• 6
• 5
• 4
• 3
• 2
• 1

#045

• 6
• 5
• 4
• 3
• 2
• 1

#050 #051

• 6
• 5
• 4
• 3
• 2
• 1

#060

• 6
• 5
• 4
• 3
• 2
• 1

10 50 90 130 #070 10 50 90 130 #080 10 50 90 130

• 6
• 5
• 4
• 3
• 2
• 1

#120

neutrino driven wind inner “delayed”

• uter

“prompt”

final abundances: neutrino driven winds

1 2 3 30 40 50 60 70 80 90

• verproduction, log10 X/X⊙

mass number, A νp-proc. without

A < 85 elements are produced via νp-process

physical uncertainties: Ye

Ye, cor = 0.5 + (Ye − 0.5) ×

• 1 + pcor

100

• ver 10% reductions are becoming

unphysical for current model

• 3
• 2
• 1

0.20 0.30 0.40 0.50 mass fraction electron fraction, Ye Ye (standard)

• 3
• 2
• 1

0.20 0.30 0.40 0.50 mass fraction electron fraction, Ye Ye - 10%

• 3
• 2
• 1

0.20 0.30 0.40 0.50 mass fraction electron fraction, Ye Ye - 20% 0.20 0.30 0.40 0.50

• 3
• 2
• 1

mass fraction electron fraction, Ye Ye - 30%

Ye uncertainties with observation

Metal poor stars ( weak r-process )

• 5
• 4
• 3
• 2
• 1

30 40 50 60 70 80 abundance, log10 YZ atomic number, Z standard pcor = 10 pcor = 30 pcor = 40 HD122563

• 7
• 6
• 5
• 4
• 3
• 2

40 80 120 160 200 abundance, log10 YA standard pcor = 10 pcor = 30 pcor = 40 solar

• 9
• 8
• 7
• 6
• 5
• 4
• 3

40 80 120 160 200 abundance, log10 YA mass number, A NDW delayed prompt

solar system ( strong r-process )

conclusion

• r-process nucleosynthesis
• reproduce A～110 r-element ( “weak” r-process )
• 2nd peak is the limit within the physical uncertainty
• “strong” r-process require 30% decrease of Ye‘s

→ need different model ( multi-D, progenitor, EoS etc. )

• neutrino driven wind
• similar environment to normal CC-SNe
• A ～ 90 proton-rich isotopes ( νp-process )

Jet-like SN induced by Magnetic fields

• neutron stars have strong magnetic fields
• neutron stars ( pulsars ) : ～ 1012 G
• magnetar : ～ 1015 G ( ～ 1 % of the neutron stars )
• Jet-like Explosions
• GRB central engine
• Hypernovae

jet/hypernova image

• 1

1 12 14 16

B ～ 1015 G

• mag. field

Zhang (2000) APJL

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

60 80 100 120 140 160 180 200 220 240

Mass Number

10−7 10−6 10−5 10−4 10−3 10−2

Ejected Mass [M]

red : includes neutrino green : no neutrino

M ej = 0.672 x 10-2 M

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

movie

ejected r-elem. mass M r-elem. ～ 10-3 to 10-2 M ( typically )