arXiv subjects

Ivo Rolf Seitenzahl

Publications and source records attributed to Ivo Rolf Seitenzahl.

3 recordsLinked to original sources

arXiv2026

Deciphering the explosion mechanism of Type Ia SNe using their remnants II: a deep dive into double detonations with SNR 0509-67.5

Type Ia supernovae (SNe) occur when a white dwarf (WD) explodes via runaway thermonuclear burning. Till date, major uncertainties remain regarding the nature of the explosion mechanism and its observable signatures. In this work, we study how the double detonation explosion mechanism, or a helium shell detonation in a sub-Chandrasekhar WD followed by a core detonation, shapes supernova remnants (SNRs) and encodes information about the WD progenitor. We evolve a suite of double-detonation SN models to the remnant phase, up to several centuries after explosion, and measure the characteristic sizes of substructures formed in the SNR due to turbulent mixing. By comparing our models to high-resolution optical observations of the young Type Ia SNR 0509-67.5, we find that the size distribution of its small-scale substructures is consistent with a double detonation explosion mechanism and further places constraints on the carbon-oxygen core mass and helium shell mass of the WD progenitor. The observed sizes of iron-dominated and sulfur-dominated substructures in SNR 0509-67.5 indicate a progenitor core mass and a shell mass of 1 solar mass and greater than 0.05 solar mass, respectively.

astro-ph.HE↗

arXiv2026

Helium emission from Balmer-dominated shocks in Type Ia supernova remnants provides constraints to their progenitor systems

Balmer-dominated shocks in Type Ia supernova remnants offer powerful probes into collisionless shock physics and hints towards supernova progenitor environments. Prior studies focused on the hydrogen Balmer lines, which manifest as a superposition of broad and narrow emission lines. Using integral-field spectroscopy with MUSE, we discovered broad and narrow helium emission lines from Balmer-dominated filaments of three Type Ia supernovae remnants in the Large Magellanic Cloud: SNR 0509-67.5, SNR 0519-69.0 and N103B. We detect broad and narrow He~\textsc{i} 5876~Å~,7065~Å emission in SNR 0519 and N103B and He \textsc{ii} 8236~Å in SNR 0519. In SNR 0509 we detect narrow He~\textsc{i} 5015~Å, 6678~Å, 7065~Å and 7281~Å, with only 7065~Å~ exhibiting a broad component. The detection of narrow He\,\textsc{ii} challenges existing shock models, where such emission is not expected, and may indicate either incomplete ion-ion equilibration behind the shock or an origin in shock precursors. For SNR 0509 and N103B, the neutral He/H line ratios indicate enhanced helium abundances, whereas SNR 0519 is consistent with the primordial He/H value. We therefore propose helium emission in Balmer-dominated shocks as a new diagnostic of shock physics and Type Ia supernova circumstellar environments. Although our modeling is primarily a proof of concept, it demonstrates the possibility to infer the total He-to-H abundance ratio, with dominant uncertainties arising from the assumed initial ionization fractions. Despite the uncertainties, we demonstrate that narrow helium lines can serve as effective probes of circumstellar conditions and progenitor evolution when analysed alongside reliable constraints on the preshock neutral H/He abundance ratio.

astro-ph.SR↗

arXiv2010

Nucleosynthesis in thermonuclear supernovae with tracers: convergence and variable mass particles

Nucleosynthetic yield predictions for multi-dimensional simulations of thermonuclear supernovae generally rely on the tracer particle method to obtain isotopic information of the ejected material for a given supernova simulation. We investigate how many tracer particles are required to determine converged integrated total nucleosynthetic yields. For this purpose, we conduct a resolution study in the number of tracer particles for different hydrodynamical explosion models at fixed spatial resolution. We perform hydrodynamic simulations on a co-expanding Eulerian grid in two dimensions assuming rotational symmetry for both pure deflagration and delayed detonation Type Ia supernova explosions. Within a given explosion model, we vary the number of tracer particles to determine the minimum needed for the method to give a robust prediction of the integrated yields of the most abundant nuclides. For the first time, we relax the usual assumption of constant tracer particle mass and introduce a radially vary- ing distribution of tracer particle masses. We find that the nucleosynthetic yields of the most abundant species (mass fraction > 10E-5) are reasonably well predicted for a tracer number as small as 32 per axis and direction - more or less independent of the explosion model. We conclude that the number of tracer particles that were used in extant published works appear to have been sufficient as far as integrated yields are concerned for the most copiously produced nuclides. Additionally we find that a suitably chosen tracer mass distribution can improve convergence for nuclei produced in the outer layer of the supernova where the constant tracer mass prescription suffers from poor spatial resolution.

astro-ph.SR↗