Three-dimensional Simulation of Double Detonations in the Double-degenerate Model for Type Ia Supernovae and Interaction of Ejecta with a Surviving White Dwarf Companion

Abstract

We study the hydrodynamics and nucleosynthesis in the double-detonation model of Type Ia supernovae (SNe Ia) and the interaction between the ejecta and a surviving white dwarf (WD) companion in the double-degenerate scenario. We set up a binary star system with 1.0M and 0.6M carbon-oxygen (CO) WDs, where the primary WD consists of a CO core and helium (He) shell with 0.95 and 0.05M , respectively. We follow the evolution of the binary star system from the initiation of a He detonation, ignition and propagation of a CO detonation, and the interaction of SN ejecta with the companion WD. The companion (or surviving) WD gets a flung-away velocity of ∼ 1700 km s −1 , and captures 56 Ni of ∼ 0.03M , and He of 3 × 10 −4 M . Such He can be detected on the surface of surviving WDs. The SN ejecta contains a "companion-origin stream", and unburned materials stripped from the companion WD (∼ 3 · 10 −3 M ), although the stream compositions would depend on the He shell mass of the companion WD. The ejecta has also a velocity shift of ∼ 1000 km s −1 due to the binary motion of the exploding primary WD. These features would be prominent in nebular-phase spectra of oxygen emission lines from the unburned materials like SN 2010lp and iPTF14atg, and of blue-or red-shifted Fe-group emission lines from the velocity shift like a part of sub-luminous SNe Ia. We expect SN Ia counterparts to the D 6 model would leave these fingerprints for SN Ia observations.

Double detonations of sub-MCh CO white dwarfs: variations in Type Ia supernovae due to different core and He shell masses

“…Furthermore, our simulations are among the first to be carried out in full 3D (e.g. see Moll & Woosley 2013;Tanikawa et al 2018). Since M10_05 is set up in the same way as M2a in Gronow et al (2020) a comparison to Model 3 of Fink et al 2010 (FM3 hereafter) is also possible.…”

“…The model presented in Tanikawa et al (2018) also has a similar setup with a 0.95 M core and a 0.05 M shell. Their calculations are carried out with an SPH code in 3D considering a small nuclear network of 13 species in the hydrodynamics.…”

“…WDs can interact with another WD (double degenerate scenario) (e.g. Whelan & Iben 1973;Webbink 1984;Kashyap et al 2015;Tanikawa et al 2018;Rebassa-Mansergas et al 2019) or with another star, such as a He star, (single degenerate scenario) in a binary system (e.g. Whelan & Iben 1973;Dave et al 2017).…”

A hyper-runaway white dwarf in Gaia DR2 as a Type Iax supernova primary remnant candidate

“…The expected tell-tale kinematic signature (i.e. > 1,000 km s −1 in all cases) indicates LP 93-21 should still be possessing a much quicker total speed if it were ejected as a WD in the DD scenario (Shen et al 2018a;Tanikawa et al 2018). This is also indicated by Figure 1.…”

Progenitor and explosion models of type Ia supernovae

“…In particular, we have focused on interaction of the heavier WD explosion with the lighter WD. First, we have performed SPH simulation to follow the explosion of the heavier CO WD with 1.0M ⊙ , and response of the lighter CO WD with 0.6M ⊙ [30]. The SPH simulations are couple with nuclear reaction networks, and have several ten million particles owing to our massively parallel simulation code.…”