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Evolutions of starsjust below the critical massfor iron core formation
Koh Takahashi, Hideyuki Umeda, & Takashi Yoshida
Department of Astronomy, University of Tokyo
9-11Moの恒星のコア進化
Introduction9-11Mo stars evolution
・Fe core formation→ CCSNeMcrit =??
・complex features ・Thermal Pulse (SAGB)
・ONeMg core ??→ ECSNe
Introduction9-11Mo stars evolution
・calculate with large nuclear reaction network (282 species of nuclei : from n, H to Br)
and with fine initial mass grid (ΔM = 0.01Mo)
1 1 79
・Poelarends et al. (2008)・Nomoto & Hashimoto (1988)
center T-rho diagram
Fe core
O+Ne+Mg core→・ONeMg WDs?・ECSNe ?
→ CCSNe
Mcrit ?
TH ~10^7 yr
TC ~10^4 yr
THe ~10^6 yrHe
H
CNe+O+Si
7
7.5
8
8.5
9
9.5
10
0 2 4 6 8 10
log
T c [K
]
log !c [g/cc]
M=9 MoM=10 Mo
7
7.5
8
8.5
9
9.5
10
0 2 4 6 8 10
log
T c [K
]
log !c [g/cc]
M=9 MoM=10 Mo
Mcrit ?
center T-rho diagram
Fe core
O+Ne+Mg core→・ONeMg WDs?・ECSNe ?
→ CCSNe
TH ~10^7 yr
TC ~10^4 yr
THe ~10^6 yrHe
H
CNe+O+Si
1e-05
0.0001
0.001
0.01
0.1
1
0 0.5 1 1.5 2
mas
s fra
ctio
n
mass[M/Mo]
HHe
CO
NeMgSiFe
9Mo(beginning of TP) : ONeMg coreO Ne
Mg
He H
7
7.5
8
8.5
9
9.5
10
0 2 4 6 8 10
log
T c [K
]
log !c [g/cc]
M=9 MoM=10 Mo
Mcrit ?
center T-rho diagram
Fe core
O+Ne+Mg core→・ONeMg WDs?・ECSNe ?
→ CCSNe
TH ~10^7 yr
TC ~10^4 yr
THe ~10^6 yrHe
H
CNe+O+Si
10Mo(before Core Collapse) : Fe core
1e-05
0.0001
0.001
0.01
0.1
1
0 0.5 1 1.5 2
mas
s fra
ctio
n
mass[M/Mo]
HHe
CO
NeMgSiFe
Fe
Si
O He
7
7.5
8
8.5
9
9.5
10
0 2 4 6 8 10
log
T c [K
]
log !c [g/cc]
M=9 MoM=10 Mo
center T-rho diagram
Fe core
O+Ne+Mg core→・ONeMg WDs?・ECSNe ?
→ CCSNe
TH ~10^7 yr
TC ~10^4 yr
THe ~10^6 yrHe
H
CNe+O+Si
degenerate core Mcrit ?
・for Fe core formation, Mcrit = ?・degenerate core evolution
Results
7
7.5
8
8.5
9
9.5
10
0 2 4 6 8 10
log
T c [K
]
log !c [g/cc]
M/Mo=99.59.79.8
9.789.79
9.99.81
1011
8.4
8.6
8.8
9
9.2
9.4
5.5 6 6.5 7 7.5 8 8.5 9 9.5 10
log
T c [K
]
log !c [g/cc]
M/Mo=99.59.79.8
9.789.79
9.99.81
1011
Results
Mcrit ~ 1.37 Mo(9.7 Mo) for Ne burning
1.71
1.27
1.491.40
1.401.38
1.370
1.3691.331.29
1.373
Mcrit ~ 1.38 Mo(9.8 Mo) for Si burning
for Fe core formation, MCOcore > 1.38 Mo
・1.71 etc. : CO core mass [Mo]・ : measure point (at the end of C burning)
8.4
8.6
8.8
9
9.2
9.4
5.5 6 6.5 7 7.5 8 8.5 9 9.5 10
log
T c [K
]
log !c [g/cc]
M/Mo=99.59.79.8
9.789.79
9.99.81
1011
some features
②Ne+O+Si pulsefor 9.9Mo
① property changefor 9.8Mo
8.4
8.6
8.8
9
9.2
9.4
5.5 6 6.5 7 7.5 8 8.5 9 9.5 10
log
T c [K
]
log !c [g/cc]
M/Mo=99.59.79.8
9.789.79
9.99.81
1011
some features
②Ne+O+Si pulsefor 9.9Mo
① property changefor 9.8Mo
9.8Mo : beginning of Ne burning
Si
ONe
Mg
1e-05
0.0001
0.001
0.01
0.1
1
0 0.5 1 1.5 2
mas
s fra
ctio
n
mass[M/Mo]
HHe
CO
NeMgSiFe
8.4
8.6
8.8
9
9.2
9.4
5.5 6 6.5 7 7.5 8 8.5 9 9.5 10
log
T c [K
]
log !c [g/cc]
M/Mo=99.59.79.8
9.789.79
9.99.81
1011
some features
②Ne+O+Si pulsefor 9.9Mo
① property changefor 9.8Mo
9.8Mo : Ne burning terminationSiO
Ne
Mg
1e-05
0.0001
0.001
0.01
0.1
1
0 0.5 1 1.5 2
mas
s fra
ctio
n
mass[M/Mo]
HHe
CO
NeMgSiFe
・electron capture on O products
MCh = 1.46(2Ye)^2 Mo
0.4
0.5
0.6
0.7
0.8
0.9
0 0.5 1 1.5 2
elec
mol
e fra
ctio
n
mass[M/Mo]
① electron capture for 9.8Mo
Ye ~ 0.48
8.4
8.6
8.8
9
9.2
9.4
5.5 6 6.5 7 7.5 8 8.5 9 9.5 10
log
T c [K
]
log !c [g/cc]
M/Mo=99.59.79.8
9.789.79
9.99.81
1011
some features
②Ne+O+Si pulsefor 9.9Mo
① property changefor 9.8Mo
8.4
8.6
8.8
9
9.2
9.4
5.5 6 6.5 7 7.5 8 8.5 9 9.5 10
log
T c [K
]
log !c [g/cc]
M/Mo=99.59.79.8
9.789.79
9.99.81
1011
some features
②Ne+O+Si pulsefor 9.9Mo
① property changefor 9.8Mo
9.9Mo : Ne+O+Si burning → Fe shellSiO
Ne
Mg
1e-05
0.0001
0.001
0.01
0.1
1
0 0.5 1 1.5 2
mas
s fra
ctio
n
mass [M/Mo]
HHe
CO
NeMgSiFe
8.4
8.6
8.8
9
9.2
9.4
5.5 6 6.5 7 7.5 8 8.5 9 9.5 10
log
T c [K
]
log !c [g/cc]
M/Mo=99.59.79.8
9.789.79
9.99.81
1011
some features
②Ne+O+Si pulsefor 9.9Mo
① property changefor 9.8Mo
9.9Mo : Ne+O+Si burning → Fe shell
1e-05
0.0001
0.001
0.01
0.1
1
0 0.5 1 1.5 2
mas
s fra
ctio
n
mass[M/Mo]
HHe
CO
NeMgSiFe
Fe
Si
ONe
Mg
8.4
8.6
8.8
9
9.2
9.4
5.5 6 6.5 7 7.5 8 8.5 9 9.5 10
log
T c [K
]
log !c [g/cc]
M/Mo=99.59.79.8
9.789.79
9.99.81
1011
some features
②Ne+O+Si pulsefor 9.9Mo
① property changefor 9.8Mo
Summary
・We have calculated the evolution for 9-11Mo stars with large nuclear reaction network.
・The critical mass for Ne ignition is 1.37Mo for CO core, 9.7Mo for ZAMS.・The critical mass for Si ignition is 1.38Mo for CO core, 9.8Mo for ZAMS.
ご清聴ありがとうございました
・In an electron degenerate core, effects of neutrino cooling and elec. capture are important.
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