Accreting white dwarf models for type I supernovae. I. Presupernova evolution and triggering mechanisms
The evolution of carbon-oxygen white dwarfs accreting helium in binary systems has been investigated from the onset of accretion up to the point at which a thermonuclear explosion occurs as a plausible explosion model for a Type I supernova. Although the accreted material has been assumed to be helium, our results should also be applicable to the more general case of accretion of hydrogen-rich material, since hydrogen shell burning leads to the development of a helium zone. Several cases with different accretion rates of helium and different initial masses of the white dwarf have been studied. The relationship between the conditions in the binary system and the triggering mechanism for the supernova explosion is discussed, especially for the cases with relatively slow accretion rate. It is found that the growth of a helium zone on the carbon-oxygen core leads to a supernova explosion which is triggered either by the off-center helium detonation for slow and intermediate accretion rates, or by the carbon deflagration for slow and rapid accretion rates. Both helium detonation and carbon deflagration are possible for the case for the slow accretion since, in this case, the initial mass of the white dwarf is an important parameter for determining the mode of ignition. Finally, various modes of building up the helium zone on the white dwarf, namely, direct transfer of helium from the companion star and the various types and strength of the hydrogen shell flashes are discussed in some detail.
- Research Organization:
- Laboratory for Astronomy and Solar Physics, Goddard Space Flight Center, Greenbelt, Maryland
- OSTI ID:
- 5024087
- Journal Information:
- Astrophys. J.; (United States), Vol. 253:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
SUPERNOVAE
STAR MODELS
WHITE DWARF STARS
STAR ACCRETION
STAR EVOLUTION
BINARY STARS
CARBON
HELIUM
HELIUM BURNING
OXYGEN
STAR BURNING
DWARF STARS
ELEMENTS
ERUPTIVE VARIABLE STARS
FLUIDS
GASES
MATHEMATICAL MODELS
NONMETALS
RARE GASES
STARS
VARIABLE STARS
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