Alessandro Chieffi
(Istituto di Astrofisica Spaziale e Fisica Cosmica & INAF)
Email: [email protected]
25 MO
5 MO
1 MO
REMEMBER that:
The interplay between the evolution of a star and the nuclear processes occurs
through the RATES and NOT the cross sections:
Rlk => Xl x Xk x screening x <sv>lk
25 MO
Dt(H-burn)= - 0.3%
CNO cycle
M(He) => 8.3 to 8.6 MO
<sv>3a x 10 is NOT appreciable
14N(p,g)15O x 10
5 MO
CNO cycle
Dt(H-burn)= - 4%
M(He) => 0.91 to 0.97 MO
1 MO
PP chain
+
Dt(H-burn)= - 3% p(p,e n)d
HB
RGB
TO
MS
Z=10-4
Y=0.23
Solid => reference
Dashed => (14N(p,g)15O) / 2
10 Gyr
13 Gyr
Red – reference
Blue – 14N(p,g)15O / 2
M=0.8 MO
Y=0.23
Z=10-4
DMHe = 1%
DMbol(tip) = 0.055 Mag
-0.04 Mag => - 0.6 Gyr
AGB phase
0.7 < M / MO < 7
He burning shell
R(Hshell) ~10-5 Rstar
CO
He (+C) intershell
core
Neutron production
H burning shell
s process
nucleosynthesis
H-rich mantle
Convective envelope
H shell
M(MO)
He shell
t(yr)
Convective envelope
H shell
M(MO)
He conv. shell
He shell
t(yr)
-1 8.5 7.5
Base conv. env.
H burn. shell
He burn. shell
Log(Surf. C abund.)
Log(Tmax He shell)
Log(T base conv. Env.)
-3 8.1 6.5
He luminosity
M=3 MO Z=0.02 Y=0.284
Network:
H to Si (full)
+
Neutron captures on:
Fe
Kr84 – Rb – Sr – Y – Zr92
Xe132 – Cs – Ba – La – Ce – Pr – Nd144
Hg202 – Tl – Pb – Bi209
92 nuclei
Element
Log10(PF)
Log10(PF)
Stable Isotopes
M=3 MO - Z=0.02
Reference
3a / 2
3a x 2
14Npg
/2
SURFACE CARBON ABUNDANCE
Reference
3a / 2
3a x 2
14Npg
/2
The mother of all rates:
12C(a,g)16O
Roadmap...
1) WR stars: evolution & explosive nucleosynthesis
120
35
2) Intermediate Mass Stars: elemental yields