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Merging White Dwarfs

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Contact: F.X.Timmes
my one page vitae,
full vitae,
research statement, and
teaching statement.
Mergers II (2012)
In this paper by Fryer et al we combine population synthesis, merger, and explosion models with radiation-hydrodynamics light-curve models to study the implications of such a progenitor scenario on the observed white dwarf supernova population. Our standard model, assuming double-degenerate mergers produce thermonuclear explosions, produces supernova light curves that are broader than the observed sample. In addition, we discuss how the shock breakout and spectral features of these double-degenerate progenitors will differ from the canonical single-degenerate explosion models.

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assumed profile of the explosion
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x-ray luminosities
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Spectra from 6 models


Mergers I (2010)
In this paper by Raskin et al we carry out a comprehensive smooth particle hydrodynamics simulation survey of double-degenerate white dwarf binary mergers of varying mass combinations in order to establish correspondence between initial conditions and remnant configurations. We find that all but one of our simulation remnants share general properties such as a cold, degenerate core surrounded by a hot disk, while our least massive pair of stars forms only a hot disk. We also find that some of our simulations with massive white dwarfs exhibit helium detonations on the surface of the primary star before complete disruption of the secondary. However, these helium detonations are insufficiently energetic to ignite carbon, and so do not lead to prompt carbon detonations.

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initial conditions are important!
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0.8 + 0.8 M evolution
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0.8 + 0.8 M final configuration
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0.8+0.8 M, x-z plane slice
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0.96+1.06 M, 4He detonation
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0.64+1.06 M, 4He detonation