2022 ApJL 932 L24 The origins of type Ia supernovae (SNe Ia) are still debated. Some of the
leading scenarios involve a double detonation in double white dwarf (WD)
systems. In these scenarios, helium shell detonation occurs on top of a
carbon-oxygen (CO) WD, which then drives the detonation of the CO-core,
producing a SN Ia. Extensive studies have been done on the possibility of a
double helium detonation, following a dynamical helium mass-transfer phase onto
a CO-WD. However, 3D self-consistent modeling of the double-WD system, the mass
transfer, and the helium shell detonation have been little studied. Here we use
3D hydrodynamical simulations to explore this case in which a helium detonation
occurs near the point of Roche lobe overflow of the donor WD and may lead to an
SN Ia through the dynamically driven double-degenerate double-detonation (D6)
mechanism. We find that the helium layer of the accreting primary WD does
undergo a detonation, while the underlying carbon-oxygen core does not, leading
to an extremely rapid and faint nova-like transient instead of a luminous SN Ia
event. This failed core detonation suggests that D6 SNe Ia may be restricted to
the most massive carbon-oxygen primary WDs. We highlight the nucleosynthesis of
the long-lived radioisotope $^{44}$Ti during explosive helium burning, which
may serve as a hallmark both of successful as well as failed D6 events which
subsequently detonate as classical double-degenerate mergers.
- 3D Hydrodynamical Simulations of Helium-Ignited Double-degenerate White Dwarf Mergers
- Niranjan RoyVishal TiwariAlexey BobrickDaniel KosakowskiRobert FisherHagai B PeretsRahul KashyapPablo Lorén-AguilarEnrique García-Berro
- arXiv.org
- English
- Department of Physics
- Preprint
- 9914418249501301