Charla de nucleosintesis Teresa Kurtukian Nieto INAOE
1. Nucleosíntesis en estrellas UPM muy pobres
en metales y evolución química de las galaxias
Teresa Kurtukian-Nieto
IEM-CSIC,
Serrano 121, Madrid
Teresa.kurtukian@iem.cfmac.csic.es
27 de Noviembre de 2023
3. Las reacciones nucleares se detienen a T ~ 8. 108 K
Por debajo de (∼3 · 1010 K),
los protons y los neutrones
están en equilibrio
4. 4
Metalicidad y Poblaciones de estrellas
Población I: estrellas ricas en metales.
Estrellas jóvenes.
Ejemplos: el sol o las pléiades
Población II: estrellas pobres en metales.
Estrellas viejas de una edad de hasta 13 000 millones de años,
que han explotado para dar origen a la población I.
Ejemplo: estrellas rezagadas azules en M80
Población III: sin metales.
Estrellas primigenias, después del Big Bang que han explotado para
dar origen a la pobación II. Son de la edad del Universo
Metal en astronomía : todo aquel elemento más pesado que el 4He
The Pleiades. Credit:
NASA/ESA/AURA/Caltech
8. Howes, L., Casey, A., Asplund, M. et al. Extremely metal-poor
stars from the cosmic dawn in the bulge of the Milky Way.
Nature 527, 484–487 (2015).
1D LTE
3D NLTE
Abundancias Astronucleares
10. MNRAS 489, 1697–1708 (2019)
Enrichment of the Galactic disc with neutron-capture elements: Mo
and Ru
T. Mishenina, M. Pignatari, T. Gorbaneva, C. Travaglio, B. Coté, F.-K. Thielemann and C. Soubiran
Evolución química galáctica
11. Nucleosynthesis : interdisciplinary field
Nuclear physics
Theory &
experiments
Galactic chemical
evolution models
Astrophysical
site modelelling
Nuclear
Reaction
network
calculations
Astronomical
observations
12. The Nuclide chart: a stellar prespective
BIG BANG Nucleosynthesis
HYDROGEN burning
HELIUM burning
ADVANCED quiescent burnings
EXPLOSIVE burnings
SLOW n-capture process
INTERMEDIATE n-capture process
RAPID n-capture process
p-process (n-deficient SS)
13. Nucleosynthesis up to the iron peak
BIG BANG Nucleosynthesis
HYDROGEN burning
HELIUM burning
ADVANCED quiescent burnings
EXPLOSIVE burnings
The Nuclide chart: a stellar prespective
14. BIG BANG Nucleosynthesis
• Main products of BBN are H (≈75%) and 4He (≈25%), plus
tiny amounts of D, 3He, 6Li and 7Li;
• The nuclear network needed to follow BBN is quite small!
16. Nucleosynthesis up to the iron peak
HYDROGEN burning
The CNO cycle is the dominant H-burning mechanism in upper Main Sequence stars (M>1.5 Ms).
17. HELIUM burning
THE HOYLE STATE
This process occurs thanks to the famous Hoyle state,
with an excitation energy of about 7.6 MeV in 12C.
After its prediction, it was found experimentally, being one of the triumphs of nuclear astrophysics.
18. ADVANCED quiescent burnings
In massive stars the gravitational collapse increases the core
temperature and density enough to ignite advanced burnings:
• C-burning
• O-burning
• Ne-burning
• Si-burning
M=15 MSUN
19. Uncertainty in the 16O+16O rate
The 16O+16Ofusion reaction is a key reaction for the later oxygen burning phase of massive stars (M > 8 Ms),
influencing also the carbon burning phase.
Theoretical predictions at relevant energies
of the astrophysical factor show different
behaviours!
20. Uncertainty in the 16O+16O rate
The combination of most sophisticated devices worldwide at LNL, Italy (AGATA, GRIT,
NEDA, SUGAR) makes the experimental study of 16O+16O at low energies feasible
21. SUGAR: Supersonic GAs Jet taRget
A extremely thin pure target (if gas is a molecular element,
example N2).
Thickness around 1018 atoms/cm2.
The jet target is well defined, enclosed in a small area.
Better than “gas target” and/or “cryogenic target”.
The DVS allow a windowless system, i.e.:
No other nuclei interacts with the beam, just the gas injected in
the chamber.
Better than “gas target” and/or “cryogenic target”.
The thin target allows to perform experiments at very low
energies, ensuring forward scattering (ideal for nuclear
astrophysics experiments but also for low energy accelerators).
While the gas lasts, jet target will be there, it doesn’t break.
SUGAR is a device developed at IFUNAM, Mexico
23. EXPLOSIVE burnings
In neutron rich environments, the reaction 9Be(α,n)12C may
dominate over the 3α reaction, depending on the astrophysical
conditions.
The relevance of this process has been linked to
the nucleosynthesis by rapid neutron capture
(or r process) in type II supernovae.
26. Neutron Pathways to Nucleosynthesis
The r process
(neutrino-wind, NS mergers, jet-SNe, etc)
Nn > 1020 n cm-3;
The n process
(explosive He-burning in CCSN)
1018 n cm-3 < Nn < 1020 n cm-3;
The i process
(H ingestion in convective He burning conditions)
1014 n cm-3 < Nn < 1016 n cm-3;
Neutron capture triggered by the 22Ne(α,n)25Mg
in massive AGB stars and super-AGB stars
Nn < 1014 n cm-3;
The s process
AGB stars, massive stars
and fast rotators Nn < few 1012 n cm-3 .
p-> photodesintegration
Nucleosynthesis of trans-iron elements
28. s-process: theory
Proton
number
65
66 67 68
69
70
70
71
72 73 74
76
75
76
77 78
79
80
80
81
82 83 84
82
85
86 87 88
89
87
86
90 91 92
Cu
Zn
Ge
As
Rb
Ga
Kr
Br
Se
Zr
Y
Sr
N=50
The s-process proceeds closely stick
to the β-stability valley.
29. The physics of the i-process
AGB stars @low Z
CO Core
He-shell
H-shell
Rapidly Accreting White Dwarfs
(RAWD)
30. The i-process theory
Proton
number
65
66 67 68
69
70
70
71
72 73 74
76
75
76
77 78
79
80
80
81
82 83 84
82
85
86 87 88
89
87
86
90 91 92
Cu
Zn
Ge
As
Rb
Ga
Kr
Br
Se
Zr
Y
Sr
N=50
31. The i-process theory
Proton
number
65
66 67 68
69
70
70
71
72 73 74
76
75
76
77 78
79
80
80
81
82 83 84
82
85
86 87 88
89
87
86
90 91 92
Cu
Zn
Ge
As
Rb
Ga
Kr
Br
Se
Zr
Y
Sr
N=50
i process
Nn ~ 1014-17 n/cm3
32. The i-process theory
Proton
number
65
66 67 68
69
70
70
71
72 73 74
76
75
76
77 78
79
80
80
81
82 83 84
82
85
86 87 88
89
87
86
90 91 92
Cu
Zn
Ge
As
Rb
Ga
Kr
Br
Se
Zr
Y
Sr
N=50
i process
Nn ~ 1014-17 n/cm3
33. The rapid neutron capture process
Astrophysical environment
should provide enough neutrons
per seed for the r process to
operate
𝐴final = 𝐴initial + 𝑛seed
nseed depends mainly on
neutron richness ejecta
requires properties of exotic neutron-
rich nuclei:
• Beta-decay rates
• Neutron capture rates
• Fission rates and yields
47. The production of molybdenum in stars:
a nuclear astrophysics challenge
92Mo : p-process only
94Mo : p-process, s-process
95Mo : mixed s- and r-process (i-process)
96Mo : s-only
(shielded from 96Zr )
97Mo : mixed s- and r-process (i-process)
98Mo : mixed s- and r-process (i-process)
100Mo: r-only
48. Other reactions mechanisms for the production of
molybdenum in stars:
Mo (Z=42) ν wind SNe
Mo (Z=42) MHD SNe
49. (α,n) reactions at CMAM Madrid
87Sr(α,n)90Zr
13C(α,n)16O
Zr (Z=40)
revisited
Commissioning in 2023 CSIC-IEM
CSIC-IFIC
CIEMAT
52. Further measurements
F.M.D.Attar et al., Applied Radiation and Isotopes,Volume 184, 110192 (2022)
This reaction has a value Q=-1.7529 MeV
The Gamow window of astrophysical interest
for this reaction is
between 1887 keV and 6852 keV,
for a temperature range between
0.5 and 2 GK
87Sr(α,n)90Zr
53. Mo (Z=42) MHD Sne LNL, Italy
(α,n) reactions at LNL Italy
SUGAR+AGATA+NEDA
4He Gas Jet
54. MNRAS 489, 1697–1708 (2019)
Enrichment of the Galactic disc with neutron-capture elements: Mo
and Ru
T. Mishenina, M. Pignatari, T. Gorbaneva, C. Travaglio, B. Coté, F.-K. Thielemann and C. Soubiran
The production of molybdenum in stars:
a nuclear astrophysics challenge
57. Called the Methuselah star, HD 140283
is 190.1 light-years away. Astronomers
refined the star's age to about 14.5
billion years (which is older than the
universe), plus or minus 800 million
years.
58. Abundancias en Methuselah star, HD 140283
Rapidly Accreting White Dwarfs
(RAWD)
13C(α,n)16O
about 1015 neutrons per cm3 ,
intermediate between slow (s)
and rapid (r) neutron-capture processes,
thus called the intermediate (i-) process.
