Transcript Nuclear Astrophysics Studies

The FAIR Chance for Nuclear
Astrophysics
• Elemental Abundances
• Core-collapse Supernovae
• The neutrino process
• The r-process nuclei in -Wind
• Neutron Stars in Binaries
GSI today
SIS 100/300
Future facility
SIS 18
UNILAC
CBM
ESR
Super
FRS
Rare-Isotope
Production Target
HESR
Antiproton
Production Target
PP /
AP
FLAIR
RESR
CR
Observers
NESR
100 m
CN
DE
ES
FI
FR
GB
GR
IN
IT
PL
RO
RU
SE
GSI today
New facility FAIR
SIS 100/300
SIS 18
UNILAC
CBM
ESR
Super
FRS
Rare-Isotope
Production Target
HESR
PP /
AP
RESR
CR
Ion beams today:
Z = 1 – 92
100 m
(Protons til uranium)
Up to 2 GeV/nucleon
Antiproton
Production Target
Future beams:
FLAIR
Intensity: primary
ions 100-fold
secondary RIB 10000-fold
Types : Z = -1 – 92
NESR
(Antiprotons til uranium)
Energies: ions up to 35 - 45 GeV/u
antiprotons 0 -15 GeV/c
FAIR Start Event:
November 7, 2007
A splendid perspective and
eminent challenge !
Each heavy atom in our body was build and
processed through ~100-1000 star generations
since the initial Big Bang event!
We are made of star stuff
Carl Sagan
Signatures of Nucleosynthesis
solar abundance distribution
• nucleosynthesis processes
• nucleosynthesis history
of our universe
The stellar abundance
distribution is a reflection
of nuclear structure and
nuclear stability!
The Cosmic Cycle
Evolution of a Star
Stellar Life
Simulation of Supernova Collapse
• Electron capture on
nuclei
• Composition:
increasingly neutron
rich nuclei
• Elastic neutrino
scattering on nuclei
Courtesy: RIKEN
Weak interaction during collapse phase
Effects of Nuclear Electron Capture during
Core Collapse
The electron capture at high
densities results in lower Ye
and generates neutrino wind
which is necessary for driving
the shock.
Hix, Messer, Mezzacappa, et al ‘03
Electron captures on nuclei dominate
Two-Dimensional Supernova
Simulation
• Plasma instabilities
• Equation of State
• Neutrino transport
– Neutrino opacities
– Dense matter
correlations
– Neutrino-nucleon
reactions
• Rotation, magnetic
fields.....
Courtesy: Hans-Thomas Janka
Courtesy Hans-Thomas Janka
Explosive Nucleosynthesis
Neutrino reactions with nucleons
determine the proton-to-neutron
ratio
• Neutrino-Proton Process
(early ejecta, proton rich)
• R-Process
(late ejecta, neutron rich)
Possible consequences of high
neutrino flux in shock-front
Neutrino capture on protons
1H(+,e+)n, neutron production
which influence the reaction
path by neutron capture.
•Anti-neutrino capture on protons produce neutrons at late times
•(n,p) reactions simulate beta decays and overcome waiting points
p-process in hydrogen rich, high
neutron flux environments
On-site neutron production
through neutrino induced
interaction: 1H(+,e+)n!
By-passing waiting
point nuclei 64Ge,
68Se by n-capture
reactions.
The R-Process
•
•
•
•
•
Courtesy: K.-L. Kratz
Masses
Half lives
Neutron capture rates
Fission
Neutrino reactions
Supernova shock front nucleosynthesis
R-Process Simulation
Courtesy: Gabriel Martinez-Pinedo
FAIR Chance: Nuclear masses
• R-Process abundances
depend on neutron
separation energies
• Different mass models
predict different patterns
• FRDM: ‚robust‘ patterns,
as observed in old halo
stars in Milky Way
• ETFSI: individual patterns
strongly depending on
neutron-to-seed ratios
Mass measurements at FAIR
FAIR Chance: Role of Halflives
• Competition velocity
of ejected matter vs.
halflives
• IF halflives were
known, strong
constraint of matter
ejection from neutron
star surface!
FAIR Chance: Neutron Stars
• Neutron Stars are
laboratories for matter
at extreme densities
• Neutron rich nuclei
• Equation of State for
nuclear matter
• Exotic phases?
X-Ray Burst and RP-Process
 = 106 g/cm3
End Point
Sn
Pd
66
62
Mo
58
Sr
Waiting Points
54
Se
50
46
Zn
42
38 5 ·1038
Fe
34
Ti
30
Ar
26
22
106g/cm3
Ne
Si
18
14
C
10
He
2
6
Ignition
Luminosity [erg/s]
105g/cm3
70 74
AW max
AW min
4
3
2
1
0
100
200
Time [s]
300
Fate of ashes on neutron star
surface
Neutron star surface
Radiative
H,He Nuclear
cooling
reactions
gas
thermonuclear
ashes
ocean
outer
crust
Inner
crust
 cooling
thermonuclear
Electron
capture
pycnonuclear
Crust processes
106Pd
Ouellette, Gupta & Brown 2005
Haensel & Zdunik 1990, 2003
Beard & Wiescher 2003
Known mass
4.8 x 1011 g/cm3
106Ge
Increase with Z1Z2
56Fe
1.8 x 1012 g/cm3
68Ca
2.5 x 1011 g/cm3
56Ar
1.5 x 1012 g/cm3
34Ne
72Ca
4.4 x 1012 g/cm3
The FAIR Chance: New Horizons
The FAIR Chance: New Horizons