THE ENERGY OF STARS
NUCLEAR ASTROPHYSICS
THE ORIGIN OF THE ELEMENTS
Stellar Origin of Energy the Elements
Nuclear Astrophysics
Astrophysics Nuclear Physics ROBERT D’ESCOURT ATKINSON (1931)
1942 β
MeV n-capture cross-sections from declassified data (Hughes 1946)
G. Gamow (mid-40ies): all elements produced in the hot primordial Universe (Big Bang) by successive neutron captures
F. Hoyle (mid-40ies): all elements produced Inside stars during their pre-collapse stage, by thermonuclear reactions
Old stars of galactic halo (Population II) contain less heavy elements (metals) than the younger stellar population (Population I) of the galactic disk Chamberlain and Aller 1951 The chemical composition of the Milky Way was substantially different in the past
Existence of chemically peculiar stars WR stars , Carbon stars Tc in s-stars (Merill 1952)…….
Salpeter
Hoyle (1954) 1957 : B2FH
n from (,n) on 4N+1 nuclei 1957 : B2FH 1957 : A. G. W. CAMERON Nuclear reactions in stars and nucleogenesis
Hayashi (1950) n,p equilibrium
X(n)/X(p)~0.13 at freeze-out
X(He-4)~2 X(n) ~0.25 Primordial Nucleosynthesis Spite and Spite 1982 -Only way to produce so much He4 ( ̴25 % by mass) -Only way to produce Deuterium (destroyed in stars) -Only way to produce so much early Li7 Theoretical abundances agree with observations perfectly for D, satisfactorily for He-4,
poorly for Li-7
Nuclear reaction rates, and resulting WMAP abundances, depend on baryon density Dark baryons SBBN: Non
2 missing matter baryonic
L U M I N O U S B A R Y O N S N O Y R A B S U O N I MU L
problems dark E R T T A M G N I T A T I V A R G matter
GCR composition is heavily enriched in Li, Be, B Same order as spallation cross sections 6 (a factor ~10 for Be and B) of CNO LiBeB: σ(B) > σ(Li) > σ(Be) Solar composition: X(Li) > X(B) > X (Be) LiBeB is produced by spallation of CNO as GCR GCR composition: X(B) > X(Li) > X(Be) propagate in the Galaxy (Reeves, Fowler, Hoyle 1970)
1971 LiBeB production and evolution in the galaxy with full treatment of GCR composition and propagation and stellar sources for Li (NP 2012)
Stellar processes CNO of GCR always the same (from rotating massive stars)
Most Li from stars for (AGB, nova) but PRIMARY required yields production ~10 times larger of Be and B than theory
NP 2012
Hoyle and Fowler 1960 Explosive nucleosynthesis What powers the lightcurves of supernovae ?
B2FH
Be-7 : Borst 1950 Cf-254: Baade, B2FH and Christy 1956 Ni-56 : T. Pankey Jr 1963
Clayton, Colgate, Fishman 1969 Clayton, 70ies: yields of radioactivities
Assuming that their decay produces the solar -ray line lightcurves of SNIa abundances of their stable daughter nuclei But he missed Al-26 First -ray line from radioactivity: 1.8 MeV from Al26 ( ≈ 1 Myr) (Mahoney et al. 1982)
COMPTEL/CGRO legacy(circa 2000)
Diffuse emission from 2 M⊙/Myr of Al26, produced from 10000 SNII and WR stars Nucleosynthesis still active in the Galaxy
Tueller et al. 1989 The 847 keV line of Co56 was detected NOT from a SNIa, but from SN1987A (18 M⊙ star in LMC, at 50 kpc) Confirmation of explosive nucleosynthesis (stable Fe-56 is produced as unstable Ni-56)
Radioactivity powers the late lightcurves of supernovae Line seen 6 months earlier than expected ! Hydrodynamic instabilities mix the SN interior THE ONION-SKIN Clayton and MODEL Woosley 1974
Hoyle 1955
Also:
Iben 1962+ Paczynski 1968+ Ikeuchi 1970+ Arnett 1970+
Ikeuchi, Hayashi et al. 1971
Clayton et al. 1961
Identification of different neutron exposures for the s-abundance curve Termination of the s-process Kappeler et al. 1999
Straniero et al. 2009 Arlandini et al. 1999
Reproducing the Solar s-only distribution in a parametrized stellar environment
… and the observed heavy element distribution in low metallicity halo stars Bisterzo et al. 2010
The observed universality of the r-process abundances
contrasts with the increased scatter of r/Fe at low metallicities
Cowan et al. 2013 Large dispersion of X/Fe for elements heavier than Fe peak (s- or r-) Sr Ba Eu
Frebel 2010 -4 -3 -2 -1 [Fe/H]
Argast et al. 2004 NS mergers appear later than CCSN
in TIME
But… what about Core collapse Supernovae METALLICITY ? Neutron star mergers (high frequency, low r- yield) (low frequency, high r- yield)
A first stellar generation of massive stars only
To produce a lot of black holes (= DARK MATTER !)
…and to avoid having too many long-lived low-mass stars of low metallicity (= G-DWARF problem !) Age_vs metallicity
Galactic Chemical Evolution ingredients
Stellar properties Lifetimes of stars (Myr) (function of mass M and metallicity Z) - Lifetimes - Yields (quantities of elements ejected) - Masses of residues (WD, NS, BH)
Collective Stellar Properties - Star Formation Rate (SFR) Initial Mass Function - Initial Mass Function (IMF) He3, He4, N14, C12 to Fe-peak, C12, C13, O17, weak s-, r-, p- F19, s- Gas Flows
- Infall INTERMEDIATE MASSIVE - Outflow MASS - Radial inflows in disks LOW MASS PN SN Solar Neighborhood Constraints:
Local column densities of gas, stars, SFR
as well as
O/Fe vs Fe/H Age – Metallicity (uncertain)
Metallicity distribution (requires slow infall) Age - Metallicity Metallicity distribution O/Fe vs Fe/H (requires SNIa for late Fe) X/X⊙ at T-4.5 Gyr
Yields of massive stars Woosley-Weaver 1995
Yields of LIM stars Van den Hook and Groenewegen 1997
Yields of SNIa Iwamoto et al. 1999
Full treatment of GCR composition, propagation and nucleosynthesis for LiBeB Yields of massive stars
Most abundant
nuclei ejected
by a star
of 25 M⊙
(WW95)
Thickness of layers depends on assumptions about convection and mixing processes Abundances in each layer depend on adopted nuclear reaction rates Abundances in inner layers depend also on explosion mechanism Overall structure/evolution also depends on rotation, mass loss etc. Large uncertainties still affecting the supernova yields (amounts of elements ejected) Stellar yields vary widely with stellar mass
A lot for products of early hydrostatic burning phases
Unknown for elements E(SN)=1051 erg M(Ni56)=0.1 M⊙ near the mass-cut
Yield ratios may vary considerably
BUT the average over the IMF is always close to solar ! Observed Calculated Abundances [X/Fe] in metal poor stars of the halo
α ? Primary ! α α
α α α
α ? Chemical evolution from C to Zn : theory vs observations
Woosley-Weaver 95 Chieffi-Limongi 04
ALSO Van den Hoek and Groenewegen 1997 for IMS and Iwamoto et al 1997 for SNIa
Suppose that we routinely obtain CCSN explosions. Would this imply that we understand them ? Importance of data compilations Nuclear reaction rates Exp. Thermonucl.: Caughlan+Fowler+: 1967, 1975, 1983, 1988 NACRE I: 1999, II: 2014 Solar system abundances Semi-empirical Holmes+Wooley+Fowler: 1976 BRUSLIB 1937: Goldsmith Tsao+Silberberg 1974 (spallation) Non-SMOKER 1949: Brown n-captures: 1956: Suess-Urey Macklin+Gibbons: 1961, 1965 1973: Cameron Bao+Kappeler +: 1987, 2000 1982: Anders-Ebihara β-decays 1989: Anders-Grevesse Takahashi+Yokoi: 1987 1993: Grevesse-Sauval-Noels 2003: Lodders Massive star yields 2005: Asplund-Grevesse-Sauval 1995 Arnett Z⊙ 2-32 (He) Elm
1995 WW Z-dep 11-40 M⊙ Isot. H-Zn Z⊙ = 0.0134 from 0.02 1995 TNH Z⊙ 13-25 Isot. H-Ge 1998 PCB Z-dep 6-120 ML Sel. Isot. 2004 CL Z-dep 15-35 Isot. H-Ge 2006 Nomoto+ Z-dep 13-70 Isot. C-Zn 2006 MM+ Z-dep 9_120 ML,Rot Sel. Isot. 2013 CL Z⊙ 13-120 ML,Rot Isot. H-Mo Dust Globular cluster composition AGB, C-stars, Novae, X-bursts s-stars, WR, … Galactic Pre- Nucleo Chemical solar -ray cosmo LIM stars SN Types astronomy grains chronology Massive stars Lightcurves evolution SN remnants Convection, Stable nuclei Radioactive Mass loss Hydro 1-2-3D, -induced GCR Metallicity GR, EOS, n-captures, fission properties Solar Rotation, … -transport, … Thermonuclear Solar model Advanced phases Supernovae Hydrostatic Explosive Nuclear properties: masses, decay rates, reaction cross-sections Stellar Photometry Stellar, ISM spectroscopy 3K MWB GCR spectra Stellar Physics Cosmology Cosmic ray physics H-burn : Main Seq 3-α: Red giants Stellar Primordial Spallogenic Stellar Energy Origin of the Elements Nuclear Astrophysics Astrophysics Nuclear Physics