How Nature makes goldThe role of isotopes for the origin of the elements

K lh i L kKarlheinz LangankeGSI Helmholtzzentrum Darmstadt

AAAS Symposium, Vancouver, February 20, 2012

Signatures of NucleosynthesisSignatures of Nucleosynthesissolar abundance distributionsolar abundance distribution

NUCLEAR ASTROPHYSICS is concerned with

the origin of elements in stellar burning

the production of energy in stars and stellar explosio

• nucleosynthesis processes • nucleosynthesis history

of our universe

the production of energy in stars and stellar explosio

1010

stellar H-, He, C, O, Si-burning

stars, supernovae

s-processHe-burning in AGB stars, of our universe

100

105

Abun

danc

e

cosmic rays

p-process

r-process

type II supernovae,merging neutron stars

He-burning in AGB stars, massive stars

observational signatures are

abundance distributions

0 50 100 150 200A

10-5

p-processsite disputedThe stellar abundance

distribution is a reflection of nuclear structure and n clear stabilit ! abundance distributions

luminosities

nuclear stability!

What is an Isotope?What is an Isotope?

F i b fFor a given number ofprotons, isotopes differby their number of neutronsunstable due to beta decay

Nucleosynthesis processesNucleosynthesis processes

Star at the end of its lifeStar at the end of its life

Star has an onion like structureStar has an onion-like structure

Iron is the end-product of stellar burning

After nuclear energy sourceAfter nuclear energy sourcehas ceased, stellar corecollapses under its gravity

SUPERNOVA

Supernova collapse and explosionSupernova collapse and explosion

In about a second, the core radius ,reduces from 6000 km to 20 km

Collpase stops when the inner coreCollpase stops when the inner corecorresponds to a gigantic nucleuswith about half of a solar mass.

fMost of the gain in gravitationalenergy is released in the explosion.This energy corresponds to thegy pproduction of 100 Suns during theirentire life of 10 Billion years.

Supernova SimulationSupernova Simulation

• Recent progress:p g• Multi-dimensional

hydrodynamicshydrodynamics• Improved nuclear

inputp– Electron capture– Neutrino-induced

reactions

cCourtesy Hans-Thomas Janka

Courtesy: Hans-Thomas Janka

Electron capture during collapseElectron capture during collapse

Capture rates on nucleivs free protons

Modern many-body models predict electron capture rates whichdiffer by more than a magnitude from previous estimates.

Consequence: capture on (unstable) neutron-rich isotopes dominatethrough the entire collapse with significant impact on neutrino spectrathrough the entire collapse with significant impact on neutrino spectraand temperature-density profiles of the core

Stellar electron captureStellar electron capture

Stable nuclei are unstable under stellar conditions

Data from charge-exchange reactions: (n,p), (d,2He)

Making radioactive isotopesMaking radioactive isotopes

(p,n) charge-exchange reactions on rare isotopesM. Sasano, R.G.T. Zegers et al. PRL 107, 202501 (2011)

Extract Gamow-Teller strengths model-independently• Weak reaction rates for late stellar evolution (supernovae)

First successful experiment: 56Ni(p,n)to extract Gamow-Teller strengths for supernova unstable isotope

New method for (p,n) in inverse kinematics: applicable t ti l i f d it ti

n

RI beam

to exotic nuclei of any mass and excitation energy.•Inverse kinematics•Requires beam intensities >104 pps•Explore very neutron rich nuclei in next generation RI beam f ili i lik FRIB@MSUfacilities like FRIB@MSU

Neutron Stars: supernova remnantsNeutron Stars: supernova remnants

• Neutron Stars areNeutron Stars are laboratories for matter at extreme densities

• Neutron rich nuclei• Equation of State for

nuclear matter• Exotic phases?

Explosive hydrogen burningExplosive hydrogen burningBinary system of compact object andBinary system of compact object andcompanion star in hydrostatic burning.Mass flow induces thermonuclear explosion

White Dwarf – NovaNeutron Star – x-ray burster

Observation of gamma lines; e.g. fromelectron-positron annihilation followingbeta+ (positron) decay of unstable nuclei like 18F

Integral satellite

Novae: Explosive H burningp g

TUDA

18F(p,)15ODRAGON

Affects 22Na and 26gAl radioisotope ejecta from classical novae

reduced uncertainty for 511 keVspectrum in classical novae

14

Precision mass measurementsPrecision mass measurements

Isoltrap at CERN

Penning trap

Mass measurements performed inJyvaeskylae, Finland, for rp-process

Rp-process massesRp process masses

R flRp-process mass flow

Effect on abundance predictions

Making Gold!Making Gold!

Nature

vsvs

Humans

Old stars in galactic halo have the samer-process abundances as the solar system

Johann Friedrich Böttger, AlchemistInventor of European White Chinar process abundances as the solar system

for A>130, but not below.

two distinct r-process sites?

Inventor of European White ChinaIn Meissen, Germany

The R-ProcessThe R Process

• Masses• Half lives• Neutron capture ratesNeutron capture rates• Fission• Neutrino reactionsNeutrino reactions

Courtesy: K -L KratzCourtesy: K.-L. Kratz

Potential r-process sitesPotential r process sites

Neutrino-driven wind from a Neutron star mergersNeutrino-driven wind from anascent neutron star in a supernova explosion

Neutron star mergers

Freiburghaus et al.

Woosley et al.

R-Process at high entropy: fissionR Process at high entropy: fission

Courtesy: Gabriel Martinez-Pinedo

Next-Generation Isotope FacilitiesNext Generation Isotope Facilities

TRIUMF/ISAC

MSU/FRIBGSI/FAIR

RIKEN/RIBF

UNILACSIS 18

SIS 100/300GSI today New facility FAIR

SuperFRS

ESR Rare-IsotopeProduction Target

CBM

HESR

FRS

AntiprotonProduction TargetPP / AP

CRRESR

FLAIR

AP

Future beams:Intensity: primary ions 100-fold

d RIB 10000 f ld

Future beams:Intensity: primary ions 100-fold

d RIB 10000 f ld

100 m

NESR

CR

Ion beams today:Z = 1 – 92(Protons til uranium)

Ion beams today:Z = 1 – 92(Protons til uranium)

secondary RIB 10000-fold Types : Z = -1 – 92(Antiprotons til uranium) Energies: ions up to 35 45 GeV/u

secondary RIB 10000-fold Types : Z = -1 – 92(Antiprotons til uranium) Energies: ions up to 35 45 GeV/u100 m(Protons til uranium)

Up to 2 GeV/nucleon(Protons til uranium)Up to 2 GeV/nucleon

Energies: ions up to 35 - 45 GeV/uantiprotons 0 -15 GeV/c

Energies: ions up to 35 - 45 GeV/uantiprotons 0 -15 GeV/c

Mass measurements at FAIRMass measurements at FAIR

The RIB Chance: New HorizonsThe RIB Chance: New Horizons