nuclear theory for chemical evolution of galaxies · 2010-04-30 · stellar input for chemical...

Nuclear Theory for Chemical Evolution of Galaxies

Yong-Zhong QianUniversity of Minnesota

JINA GCE Workshop “Building Virtual Galaxies”

April 30, 2010

(based on review by Janka et al. 2007 in Physics Reports)

Friday, April 30, 2010

Stellar input for chemical evolution of galaxies

stellar evolution nucleosynthesis

end states

Type Ia & core-collapse SNe

star formation

nucleosynthesisenergy injection, mixing

gas return


Nuclear theory input for chemical evolution

nuclear reaction rates for:

hydrostatic & explosive burning

r-process, s-process, p-process, rp-process

nuclear equation of state

weak interaction rates

nuclear theory input for core-collapse SNe:


weak rates during pre-SN evolution & core collapse

mass, Ye, entropy of “Fe” core

mass of inner core


nuclear equation of state (EOS)radius of inner core at bounce

initial shock energylater neutrino luminosity


nuclear EoS & neutrino processesneutrino luminosity & spectraexplosion & nucleosynthesis


e-capture & beta-decay rates for pre-SN evolution Langanke & Martinez-Pinedo (LMP 2000)

B(G

T+)

d!/d"

[mb/

(sr 5

0 ke

V)]

51V(d,2He)51Ti Elab=171 MeV #cm<1˚

Shell-Model Calculation

Ex [MeV]

Ex [MeV]

2.14

MeV

3.62

MeV 4.

88 M

eV


smaller, non-systematic

differences for beta-decay

comparison withFuller, Fowler, & Newman

(FFN 1980, ’82, ’85)for late stages ofpre-SN evolution

1 4 7 10T9

10-4

10-3

10-2

10-1

10-4

10-3

10-2

10-1

100

! ec (s

"1)

10-15

10-12

10-9

10-6

10-3

LMPFFN

1 4 7 10T9

10-6

10-4

10-2

100

10-6

10-5

10-4

10-3

10-2

10-1

10-3

10-2

10-1

100

#7=10.7

56Fe 56Ni

#7=4.32

#7=4.32

55Co 59Co

#7=33

54Mn

#7=10.7 #7=33

60Co

further constraints onshell model calculations

from FRIB?


10 15 20 25 30 35 40Star Mass (M!)

0.005

0.010

0.015

0.020

!Y e

0.420

0.425

0.430

0.435

0.440

0.445

0.450

Y e

WWLMP

10 15 20 25 30 35 40Star Mass (M!)

-0.2

-0.1

0.0

0.1

!M

Fe (M

!)

1.4

1.6

1.8

2.0

MFe

(M!)

WWLMP

10 15 20 25 30 35 40Star Mass (M!)

-0.2

-0.1

0.0

0.1

!S

(kB)

0.6

0.7

0.8

0.9

1.0

1.1

1.2

cent

ral e

ntro

py /

bary

on (k B

)

WWLMP


10 100 1000DENSITY [109 g/cm3]

0

10

20

30

40EN

ERG

Y [M

eV]

temperatureQ (proton)Q (nuclei)chem. potential

beta-decay

e-capture

detailed GTstrength

distributionneeded

centroid & totalGT strength

mostly needed


e capture during core collapse

nuclear statistical equilibrium (NSE) has many nucleiwith significant abundances

reduction of Ye depends on the product of nuclearabundance & the corresponding e-capture rate

decreasing Ye changes NSE composition to favormore n-rich nuclei

when Z<40 & N>40 nuclei have significant abundances,more sophisticated shell model calculations needed,

but computational capability forces alternative:Random Phase Approximation (RPA)


Independent ParticleShell Model gives noGT strength for e capture on nuclei

with Z<40 & N>40

but finite temperature& residual interaction

lead to unblocking


-15 -10 -5 0

Q (MeV)

10-2

10-1

100

101

102

103

104

105

!e

c (

s-1

)

"11Ye=0.07, T=0.93

"11Ye=0.62, T=1.32

"11Ye=4.05, T=2.08


10-4

10-3

10-2

10-1

100

101

102

103

104r ec

(s-1

)

5 10 15 20 25 30 35 40

µe (MeV)

0

10

20

30

!E" e#

(MeV

)

protonheavy

0.3

0.4

0.5

Y e (Ele

ctro

n Fr

actio

n)

1

2

3

Entro

py p

er b

aryo

n

0 0.2 0.4 0.6 0.8 1−8

−6

−4

−2

0

Velo

city

(104 k

m/s

)

Enclosed Mass

Bruenn prescriptionLMP+hybrid rates


nuclear EoS, neutrino emission & interaction processes

time

Nuclear theory input for supernova neutrino emission

Qian & Woosley 1996


40 45 50 55 60 65 70 75 80 85 90Mass Number A

100

101

102

103

104Y i/Yi,!

0.5 0.52 0.54 0.56 0.58 0.6Ye

102

103

104

105

106

107

108

Y i/Yi,!

74Se

78Kr

84Sr96Ru

94Mo98Ru

102Pd

92Mo

106Cd108Cd

!p-process

!̄e + p! n + e+

without neutrinos,nuclear flow ends at

64Ge

(n, p) & (p, !)lead to heavier nuclei

Frohlich et al. 2004, ’06Pruet et al. 2005


Nuclear theory input for the r-process

possible role of neutrino-induced n emission

n-induced fission cross sections & yields

during the r-process, assuming (n, !) ! (!, n) equilibrium

neutron separation energy, beta-decay ratesboth depend on nuclear masses

macro-microscopic (e.g., FRDM) vs. ab initio (e.g., RMF) mass models

possible role of fission cycling

during freeze-out

n capture cross sections, beta-delayed n emission


nuclear theory for chemical evolution of galaxies · 2010-04-30 · stellar input for chemical...

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