The effect of helium accretion efficiency on rates of Type Ia supernovae: double detonations in accreting binaries

Abstract

The double-detonation explosion scenario of Type Ia supernovae (SNe Ia) has gained increased support from the SN Ia community as a viable progenitor model, making it a promising candidate alongside the well-known single degenerate and double degenerate scenarios. We present delay times of double-detonation SNe, in which a sub-Chandrasekhar mass carbon–oxygen white dwarf (WD) accretes non-dynamically from a helium-rich companion. One of the main uncertainties in quantifying SN rates from double detonations is the (assumed) retention efficiency of He-rich matter. Therefore, we implement a new prescription for the treatment of accretion/accumulation of He-rich matter on WDs. In addition, we test how the results change depending on which criteria are assumed to lead to a detonation in the helium shell. In comparing the results to our standard case (Ruiter et al.), we find that regardless of the adopted He accretion prescription, the SN rates are reduced by only ∼25 per cent if low-mass He shells (≲0.05 M⊙) are sufficient to trigger the detonations. If more massive (0.1 M⊙) shells are needed, the rates decrease by 85 per cent and the delay time distribution is significantly changed in the new accretion model – only SNe with prompt (<500 Myr) delay times are produced. Since theoretical arguments favour low-mass He shells for normal double-detonation SNe, we conclude that the rates from double detonations are likely to be high, and should not critically depend on the adopted prescription for accretion of He.

Merger Rates of Double Neutron Stars and Stellar Origin Black Holes: The Impact of Initial Conditions on Binary Evolution Predictions

“…These codes rely on precomputed grids of detailed stellar models and approximate treatments of the physical processes as described below. Despite the approximations, studies with this and similar codes based on the same philosophy have enabled insights into the many exotic phenomena resulting from lowand high-mass interacting binaries (e.g., recent work by Izzard et al 2004Izzard et al , 2006Izzard et al , 2009Ruiter et al 2009Ruiter et al , 2014Mennekens et al 2010;Abate et al 2013;de Mink et al 2013de Mink et al , 2014Fragos et al 2013;Vanbeveren et al 2013;Claeys et al 2014;Kochanek et al 2014;Mennekens & Vanbeveren 2014;Schneider et al 2014Schneider et al , 2015Toonen et al 2014).…”

Type Ia supernovae from exploding oxygen-neon white dwarfs

“…The double detonations show a very different DTD shape than that of the ONe systems; the peak at ∼700 Myr is simply not found in systems with ONe primaries (instead there is a peak ∼200 Myr). The lack of a later DTD peak for double detonations involving ONe WDs is due to the fact that events with delay times > ∼ 800 Myr typically involve degenerate (helium WD) donors (Ruiter et al 2014), which are not produced as frequently in binaries involving the more massive ONe primaries. For mergers involving two CO WDs, again, the DTD shape is quite different in comparison to mergers involving an ONe WD.…”

“…We find that the number of binary systems involving ONe WDs that may lead to classical (non-dynamical mass transfer) doubledetonations are about 8% of the classical CO double-detonations (see Ruiter et al 2014). Here, for CO WD primaries, we assume that only the systems in which the primaries are more massive than 0.9 M will potentially lead to thermonuclear events that are bright enough to be considered SNe Ia Ruiter et al 2014). The low-mass systems are thus excluded from being considered likely SN Ia candidates; however, we include their numbers in Table 1 for completeness.…”

“…If we restrict the sample of CO+CO mergers to those where the primary WD has at least 0.9 M , the ONe+X merger fraction is as high as 16%. We find that the number of binary systems involving ONe WDs that may lead to classical (non-dynamical mass transfer) doubledetonations are about 8% of the classical CO double-detonations (see Ruiter et al 2014). Here, for CO WD primaries, we assume that only the systems in which the primaries are more massive than 0.9 M will potentially lead to thermonuclear events that are bright enough to be considered SNe Ia Ruiter et al 2014).…”

“…Despite the uncertainties related to their ignition, we here investigate the question of how, if they do A&A 580, A118 (2015) Notes. Data are extracted from the P-MDS model of Ruiter et al (2014). All values have been normalized to the number of carbon-oxygen WD mergers (full mass range).…”