Kavli Affiliate: Lars Bildsten
| First 5 Authors: Logan J. Prust, Gabriel Kumar, Lars Bildsten, ,
| Summary:
Type Ia supernovae are triggered by accretion onto a white dwarf from a
companion which is most likely Roche lobe-filling at the time of the explosion.
The collision between the ejecta and a surviving companion carves out a conical
wake, which could manifest as an asymmetry when the ejecta reaches the remnant
phase. We simulate the companion interaction using the Athena++ hydrodynamics
solver to determine the ejecta structure for a double-degenerate type Ia
supernova. Ejecta in the wake is of lower density and higher velocity than the
unperturbed ejecta. We then evolve the ejecta for several thousand years using
the expanding-grid code Sprout. The forward shock within the wake is initially
indented, but becomes spherical after roughly a thousand years due to
transverse motion of shocked ejecta that fills the wake. The reverse shock
travels quickly within the wake, leading to an off-center convergence of the
reverse shock and leaving the remnant with an asymmetrical core. This also
draws material from the interstellar medium deep into the remnant, eventually
reaching the center. Large Rayleigh-Taylor plumes are found around the edge of
the wake, creating a toroidal structure composed primarily of ejecta. Estimates
of the thermal X-ray emission show that such remnants exhibit observable
asymmetries for thousands of years.
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