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FIVE REGIMES OF NUCLEAR BURNING IN DENSE STELLAR MATTER

FIVE REGIMES OF NUCLEAR BURNING IN DENSE STELLAR MATTER. D.G. Yakovlev. Ioffe Physical Technical Institute, St.-Petersburg, Russia. Physical conditions. Pycnonuclear burning. Thermonuclear burning. General outlook and applications. Screening in thermonuclear reactions. Summary.

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FIVE REGIMES OF NUCLEAR BURNING IN DENSE STELLAR MATTER

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  1. FIVE REGIMES OF NUCLEAR BURNING IN DENSE STELLAR MATTER D.G. Yakovlev Ioffe Physical Technical Institute, St.-Petersburg, Russia Physical conditions Pycnonuclear burning Thermonuclear burning General outlook and applications Screening in thermonuclear reactions Summary Moscow, December, 2004

  2. PHYSICAL CONDITIONS

  3. PHYSICAL STATES OF IONS Gas Strongly coupled classical system Strongly coupled quantum system

  4. Classical theory of thermonuclear reactions Reaction rate: Z1 Z2

  5. Classical theory of thermonuclear reactions Reaction rate R depends mainly on T Nobel Prize, 1967 History G. Gamow, H. Bethe, C. Critchfield, E. Salpeter, 1938 C. Von Weizsacker, A. Cameron, W. Fowler, G. Rivers Example Carbon burning: = burning time T=109 K  t~ 1 min No burning at low T! T=108 K  t~1036 yr

  6. PLASMA SCREENING IN THERMONUCLEAR REACTIONS Created by neighbors Consider: Then Two-stage process:(1) approaching the barrier (2) penetrating the barrier The reaction rate:R=R0E E>1 enhancement factor Basic ideas: Salpeter 1954, 1961 Salpeter & Van Horn 1969 DeWitt, Graboske & Cooper 1973 Thermodynamic function

  7. STRONG PLASMA SCREENING Thermonuclear regime with strong screening 1 12 1 2 + Salpeter’s model:

  8. Pycnonuclear reactions d Coulomb lattice of nuclei, T=0 Zero-point vibrations, =ion plasma frequency WKB tunneling: The reaction rate exponentially increases with growing density!

  9. PYCNONUCLEAR BURNING OF DENSE STELLAR MATTER tburn~1075 yrs tburn~0.1 s

  10. Gamow and Wildhack

  11. Later History Zel’dovich (1957) Cameron (1959) Kirzhnits (1960) Kopyshev (1964) Wolf (1965) Van Horn (1966) Salpeter & Van Horn (1969) Schramm & Koonin (1990) Err-brr-mrr!!

  12. THERMALLY ENHANCED PYCNONUCLEAR BURNING Increase T from T=0: = enhancement factor Salpeter and Van Horn 1969

  13. INTERMEDIATE THERMO-PYCNONUCLEAR BURNING Most difficult for the theory! Many attempts!

  14. FIVE REGIMES OF BURNING IN DENSE MATTER 1 2 Thermonuclear Strong screening Classical 3 Intermediate 5 4 T=0 T-enhanced Pycnonuclear

  15. TEMPERATURE DEPENDENCE

  16. GENERAL OUTLOOK

  17. CARBON IGNITION CURVE 1. Accreting massive white dwarfs -- SNIa 2. Accreting neutron stars -- superbursts

  18. Applications of pycnonuclear burning White dwarfs and neutron stars (particularly, accreting) H He C No hydrogen in WDs WDs as SN Ia X-ray bursters 106 109 Mass density, g cm-3 1010 ASHES Accreting neutron stars – soft X-ray transients 1012 BURN! 1013 Deepest burning: 48Mg+48Mg -> 96Cr

  19. SUMMARY • There are five regimes of nuclear burning • Classical thermonuclear regime is well elaborated; • other regimes – much less • The problem belongs to the physics of strongly • coupled Coulomb plasma: quantum tunneling in random • and fluctuating plasma potential • 4. Theory goes back in time!

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