Three-dimensional delayed-detonation models with nucleosynthesis for Type Ia supernovae

Abstract

We present results for a suite of fourteen three-dimensional, high resolution hydrodynamical simulations of delayed-detonation models of Type Ia supernova (SN Ia) explosions. This model suite comprises the first set of three-dimensional SN Ia simulations with detailed isotopic yield information. As such, it may serve as a database for Chandrasekhar-mass delayeddetonation model nucleosynthetic yields and for deriving synthetic observables such as spectra and light curves. We employ a physically motivated, stochastic model based on turbulent velocity fluctuations and fuel density to calculate in situ the deflagration to detonation transition (DDT) probabilities. To obtain different strengths of the deflagration phase and thereby different degrees of pre-expansion, we have chosen a sequence of initial models with 1, 3, 5, 10, 20, 40, 100, 150, 200, 300, and 1600 (two different realizations) ignition kernels in a hydrostatic white dwarf with central density of 2.9 × 10 9 g cm −3 , plus in addition one high central density (5.5 × 10 9 g cm −3 ) and one low central density (1.0 × 10 9 g cm −3 ) rendition of the 100 ignition kernel configuration. For each simulation we determined detailed nucleosynthetic yields by post-processing 10 6 tracer particles with a 384 nuclide reaction network. All delayed detonation models result in explosions unbinding the white dwarf, producing a range of 56 Ni masses from 0.32 to 1.11 M ⊙ . As a general trend, the models predict that the stable neutron-rich iron group isotopes are not found at the lowest velocities, but rather at intermediate velocities (∼3, 000 − 10, 000 km s −1 ) in a shell surrounding a 56 Ni-rich core. The models further predict relatively low velocity oxygen and carbon, with typical minimum velocities around 4, 000 and 10, 000 km s −1 , respectively. EXC 153. FKR, MF and SAS acknowledge travel support by the DAAD/Go8 German-Australian exchange program.

Abundance stratification in Type Ia supernovae – IV. The luminous, peculiar SN 1991T

“…A slightly off-centre ignition may accomplish some more mixing, so some Fe group elements could end up in the outer parts of the ejecta, while keeping a well-defined Si-rich shell. The 3D delayed detonation models from Seitenzahl et al (2013) have a stratification of the outer part of the ejecta in fair agreement with what is inferred from our model of SN 1991T. In particular, the models with few ignition spots show a larger production of 56 Ni at the expenses of IMEs.…”

LATE-TIME PHOTOMETRY OF TYPE IA SUPERNOVA SN 2012cg REVEALS THE RADIOACTIVE DECAY OF 57Co

“…Under this approximation, the mass ratio we measure here is roughly twice the corresponding 57 Fe/ 56 Fe ratio measured for the Sun (Asplund et al 2009). This value is slightly higher than the predictions of near-M Ch explosion models: W7 of Iwamoto et al (1999) predicts 1.7 times Solar, the pure turbulent deflagration models of Fink et al (2014) predict ∼1.5 times Solar, the delayeddetonation models of CO WDs of Seitenzahl et al (2013) predict ∼1.3 times Solar, the delayed-detonation models of WDs with carbon-depleted cores of Ohlmann et al (2014) predict ∼1.1 times Solar, and the gravitationally confined detonation models of Meakin et al (2009) …”

“…There is a trend that models with larger progenitor metallicity (see Seitenzahl et al 2013) and models that experience enhanced in situ neutronization (e.g., W7) yield higher 57 Ni/ 56 Ni ratios. This is naturally explained by the fact that 57 Ni is a neutron-rich isotope (28 protons, 29 neutrons) and its production relative to the self-conjugate 56 Ni (28 protons, 28 Figure 3.…”

Type Ia supernova remnants: shaping by iron bullets

“…1. Such iron clumps are expected to form in the deflagration to detonation explosion model (Seitenzahl et al 2013). Our results are presented in section 3.…”