new constraints on neutron- capture nucleosynthesis processes
DESCRIPTION
New Constraints on Neutron- Capture Nucleosynthesis Processes. Inese I. Ivans California Institute of Technology Hubble Fellows Symposium April 7, 2005. A Periodic Table of the Elements. 1. 2. H. He. BBN CR (+/-) neutron-capture. 3. 4. 4. 5. 6. 7. 8. 9. 10. Li. Be. B. C. - PowerPoint PPT PresentationTRANSCRIPT
New Constraints on Neutron-Capture Nucleosynthesis
Processes
Inese I. Ivans
California Institute of Technology
Hubble Fellows Symposium
April 7, 2005
Lanthanides
Actinides
1
3 4
11 12
19 20 21 22 23 24 25
37 38 4039 41
55
42 43
7456 57 72 73 75
87
62
88
59
9590
58 63
89
60
9491
106105104
61
9392
107 108
96 97
76
67 68666564
10310210199 10098
114113112111110
717069
116115
26 27
44
28
45
77
46
7978
29
47
30
48
80
49
81
31
13
50
82
14 15
32 33
51
8483
17 18
34 35
53
36
5452
8685
118117
5 6
16
87 9 10
2
H
Li
Na Mg
K Ca Sc Ti
Rb Sr Y Zr Nb
V
Cs Ba
Fr
La
Ra Ac
Hf Ta
Ce
W
Pr Nd
Cr Mn
Tc
Re
Th
Fe
Ru
Os
Pa
Co
Rh
Ir
Pm
Ni
Pd
Pt
U
Cu
Np
Au
Ag
Zn
Cd
Fm
Hg
Es
Ga
Sn
Cm
BiPb
PSiAl
In
Bk
Tl
Cf
Sb
Po At Rn
ErHo
S Cl
Ge
Ar
As Se Br
B
Kr
Te I Xe
He
C N O F NeBe
Tm
Md
Yb
No
Lu
Lr
Sm
Pu
Eu
Am
Gd Tb Dy
109
yy
Xx
Mo
A Periodic Table of the Elements
Xx: element symbol; yy: atomic number
BBN CRCR (+/-) neutron-capture
4
(Rolfs & Rodney 1988)
Chart of Nuclides
Solar System Abundance Distribution
=Z+N
(Cowley 1999)=Z+N
Solar System Abundance Distribution
=Z+N
SNeII
SNeIa
O,Mg massiveSi,Ca,Ti
less massive
Th,U
=Z+N
AGB
Sr,Y,Zr Ba,La Pb,Bimassive less massive
Happened very early in Galactic times: some very metal-poor stars are enormously rich in elements created in r -process (eg. [Fe/H] ~-3.1 => 1/1250 [Fe/H]sun)
Sneden, Cowan, Ivans et al 2002
Created in SNe IIMaybeProbablyLikelyPerhaps ...
The site of the rapid neutron-capture process?
Happened over longtimescales and rangeof metallicities andin equal measure inthe disk and halo
• Created in SNe II
MaybeProbablyLikelyPerhaps ...
“universality” of the r-process?
(Cowan, Sneden, Ivans et al 2001)
(Cowan et al 2002)
“universality” of the r-processmaybe not so universal
BD+17o3248 SS-rpoor
agree-mentwith Z<56&/or
heavies
(Rolfs & Rodney 1988)
Lead & bismuth: the end of the line for the s-process
In low mass (1-3Msun) AGB stars,
neutrons: 12C(p,)13N(e+,)13C(,n)16Oseeds: Fe
With decreasing metallicity, n ~ constant Fe decreasing => increasing n/Fe
=> s-process dist’n
(1998 Gallino et al.)
(Ivans et al. submitted)(Ivans et al. submitted)
CS29497-030
Largest [Pb/Fe]to date
First Bi to bemeasured in ametal-poor star
(Ivans et al. submitted)(Ivans et al. submitted)
In Summaryo CS29497-030: first abundance measurement of Bi in a metal-poor staro Bi/Pb in accord with s-process predictionso overall abundance pattern fits that of (r+s) process where s-processing includes r-process pre-enrichmento abundance of Na (and other elements sensitive to the neutron-excess) can be employed to constrain the mass of the AGB progenitor: lower mass stars go through fewer thermal, producing lower abundances of elements sensitive to the neutron excess