The evolution and explosion of massive stars. II. Explosive hydrodynamics and nucleosynthesis
- University of California Observatories/Lick Observatory, Board of Studies in Astronomy and Astrophysics, University of California, Santa Cruz, California 95064 (United States)
- General Studies Division, University of California, Lawrence Livermore, National Laboratory, Livermore, California 94550 (United States)
The nucleosynthetic yield of isotopes lighter than {ital A}=66 (zinc) is determined for a grid of stellar masses and metallicities including stars of 11, 12, 13, 15, 18, 19, 20, 22, 25, 30, 35, and 40 {ital M}{sub {circle_dot}} and metallicities {ital Z}=0, 10{sup -4}, 0.01, 0.1, and 1 times solar (a slightly reduced mass grid is employed for nonsolar metallicities). Altogether 78 different model supernova explosions are calculated. In each case nucleosynthesis has already been determined for 200 isotopes in each of 600 to 1200 zones of the presupernova star, including the effects of time dependent convection. Here each star is exploded using a piston to give a specified final kinetic energy at infinity (typically 1.2*10{sup 51} ergs), and the explosive modifications to the nucleosynthesis, including the effects of neutrino irradiation, determined. A single value of the critical {sup 12}C({alpha},{gamma}){sup 16}O reaction rate corresponding to {ital S}(300 keV)=170 keV barns is used in all calculations. The synthesis of each isotope is discussed along with its sensitivity to model parameters. The final mass of the collapsed remnant is also determined and often found not to correspond to the location of the piston (typically the edge of the iron core), but to a ``mass cut`` farther out. This mass cut is sensitive not only to the explosion energy, but also to the presupernova structure, stellar mass, and the metallicity. Unless the explosion mechanism, for unknown reasons, provides a much larger characteristic energy in more massive stars, it appears likely stars larger than about 30 {ital M}{sub {circle_dot}} will experience considerable reimplosion of heavy elements following the initial launch of a successful shock. While such explosions will produce a viable, bright Type II supernova light curve, lacking perhaps the radioactive tail, they will have dramatically reduced yields of heavy elements and may leave black hole remnants of 10 or more solar masses.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 282826
- Journal Information:
- Astrophysical Journal, Supplement Series, Vol. 101, Issue 1; Other Information: PBD: Nov 1995
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERGIANT STARS
ELEMENT ABUNDANCE
NUCLEOSYNTHESIS
SUPERNOVAE
ALPHA REACTIONS
BLACK HOLES
CARBON 12 TARGET
COMPUTER CODES
COMPUTERIZED SIMULATION
EXPLOSIONS
GAMMA RADIATION
GAMMA SPECTRA
HYDRODYNAMICS
MASS
NUCLEAR REACTIONS
OXYGEN 16
SHOCK WAVES
STAR EVOLUTION
STAR MODELS
LIGHT CURVES
MASSIVE STARS
OB STARS
STELLAR INTERIORS