Reading Type Ia explosions from their remnants
Paper: Mandal et al. 2026, ApJ, and Mandal et al. 2025, arXiv:2508.10752
Type Ia supernovae are thermonuclear explosions of white dwarfs, but which explosion channel produces them is still debated. This project uses the remnants left behind, hundreds of years later, to tell the channels apart.
In three-dimensional hydrodynamic simulations evolved from explosion to the remnant phase, turbulence breaks the ejecta into clumps. Clumps dominated by iron-group elements can end up with a different typical size from clumps dominated by intermediate-mass elements such as silicon and sulfur, and that difference depends on how the star exploded.
Tycho’s remnant. Applying the test to Chandra X-ray images of Tycho’s supernova remnant, its substructure is most consistent with a sub-Chandrasekhar-mass white dwarf undergoing a double detonation (arXiv:2508.10752).
SNR 0509-67.5. Double-detonation models evolved into the remnant phase are compared with MUSE observations of SNR 0509-67.5, where iron-dominated substructures are about 40% larger than sulfur-dominated ones. The closest match is a white dwarf with a carbon–oxygen core of about one solar mass and a helium shell above 0.05 solar masses (ApJ, 2026).
The method can be extended to other well-characterised remnants, including those whose original supernova spectra have been reconstructed from light echoes.