Structure and Evolution of Stars Lecture 7
dr
dmi r
M
Potential Energy U(r) (MeV)
Coulomb repulsion
1 r
Distance (fm)
⇥
Potential barrier (a)
Energy
E3,k
E3
(b) E2
Coulomb Proton wave barrier
E3,k
E1
E=0
rn
Energy
Potential energy (Ep)
r
E=0 Nuclear-force well Fig. 2.4: Astrophysics Processes (CUP), ©H Bradt 2008
) dN/dE (MeV
1
dN/dE (MeV
1
)
Energy (keV)
= 17
=4
4
Cowan et al.
1.00
BD+173248 CS 22892!052 CS 31082!001 HD 115444 HD 221170 SS r!process (Simmerer) SS r!process (Arlandini)
Ba
Relative log !
0.60
0.20
Nd
Ce
Dy
Gd
Er
Sm
!0.20
Yb Hf
!0.60 La !1.00
Eu
Ho
Pr Tb
!1.40
55
60
65
Tm 70
Atomic Number
75
Cowan et al. 2011
Figure 1.— Recent abundance determinations in five r-process rich stars, based upon new atomic lab data, compared with two solar system r-process only predictions. The abundances in each star have been normalized to the element Eu. After Sneden et al. (2009). Reproduced by permission of the AAS.
