Double-detonation Models for Type Ia Supernovae: Trigger of Detonation in Companion White Dwarfs and Signatures of Companions’ Stripped-off Materials

Abstract

We have studied double-detonation explosions in double-degenerate (DD) systems with different companion white dwarfs (WD) for modeling type Ia supernovae (SNe Ia) by means of high-resolution smoothed particle hydrodynamics (SPH) simulations. We have found that only the primary WDs explode in some of the DD systems, while the explosions of the primary WDs induce the explosions of the companion WDs in the other DD systems. The former case is so-called Dynamically-Driven Double-Degenerate Double-Detonation (D 6 ) explosion, or helium-ignited violent merger explosion. The supernova ejecta of the primary WDs strip materials from the companion WDs, whose mass is ∼ 10 −3 M . The stripped materials contain carbon and oxygen when the companion WDs are carbon-oxygen (CO) WDs with He shells 0.04M . Since they contribute to low-velocity ejecta components as observationally interfered for iPTF14atg, D 6 explosions can be counterparts of sub-luminous SNe Ia. The stripped materials may contribute to low-velocity C seen in several SNe Ia. In the latter case, the companion WDs explode through He detonation if they are He WDs, and through double-detonation mechanism if they are CO WDs with He shells. We name these explosions "triple" and "quadruple" detonation (TD/QD) explosions after the number of detonations. The QD explosion may be counterparts of luminous SNe Ia, such as SN 1991T and SN 1999aa, since they yield a large amount of 56 Ni, and their He-detonation products contribute to the early emissions accompanying such luminous SNe Ia. On the other hand, the TD explosion may not yield a sufficient amount of 56 Ni to explain luminous SNe Ia.

Delayed Detonation Thermonuclear Supernovae with an Extended Dark Matter Component

“…A detonation could be generated before the WDs are merged to form a single compact star (Moll et al 2014), and this detonation is initiated at the outer envelop that contains a thin and modest amount of helium (Townsley et al 2019). The converging detonation waves trigger a second detonation at the carbon-oxygen core, hence producing a prompt eruption (Moll et al 2014;Raskin et al 2014;Tanikawa et al 2019;Gronow et al 2020). While some observational results seem to favor the double-degenerate scenario (Woosley & Kasen 2011;Maoz et al 2014;Glasner et al 2018), suggesting that they might constitute the majority population of thermonuclear supernovae (Flörs et al 2019;Cheng et al 2020;Li et al 2021), some recent studies found that they could be in a tight tension with the γ-ray ejected time against nickel-mass relation (Kushnir et al 2020).…”

Exploration of Aspherical Ejecta Properties in Type Ia Supernovae: Progenitor Dependence and Applications to Progenitor Classification

“…In our results, due to the reflection symmetry, the cone shape is always paired on both sides. We expect that, if we allow a single bubble without assuming reflection symmetry, a one-sided feature can emerge, as in more general simulations such as Tanikawa et al (2019) and Gronow et al (2020).…”

“…Such a scenario is viable when the surface energy production is faster than its heat loss by convection or expansion (Jacobs et al 2016). The initial nuclear runaway can be triggered by accretion from its companion star in the single-degenerate scenario or through a violent merger in the double-degenerate scenario (see, e.g., Tanikawa et al 2015Tanikawa et al , 2019. Pure CO matter has a high ignition threshold for its high temperature (∼1-2×10 9 K; e.g., Sato et al 2015), which is shown to be difficult to trigger and sensitive to the way of contact (Dan et al 2012).…”

“…These require multidimensional low Mach number simulations of the atmosphere for multiple eddy turnover times. Multiple possibilities exist, including direct He ignition, C ignition, or ignition after the merger process when a Chandrasekhar-mass WD is formed (Dan et al 2011;Shen et al 2018;Tanikawa et al 2019). Geometric convergence in a low-mass WD is more difficult to achieve (Shen & Moore 2014).…”

Progenitor and explosion models of type Ia supernovae

“…We will investigate whether these materials can be observed by radiative transfer calculations in near future. We have also investigated whether the explosions of the heavier WDs induce the explosions of the lighter WDs by numerical simulations with various mass combinations of WDs [31]. In all the cases, we have used a CO WD with 1.0M ⊙ for the heavier WDs.…”