Vrutant studies the origins of Type Ia supernovae — the thermonuclear explosions of white dwarf stars, and among the brightest transients in the universe. Their remarkable uniformity makes them standardizable candles that anchor the cosmic distance ladder and revealed the accelerating expansion of the universe, while the iron-group elements they forge drive the chemical enrichment of galaxies. Yet the progenitor systems that give rise to them, and the mechanism that ignites and unbinds the white dwarf, remain among the long-standing open questions in stellar astrophysics.
His work approaches these questions through multi-dimensional, high-performance simulations that resolve the explosion from first principles. Using the adaptive-mesh hydrodynamics code FLASH, he models the compressible, reactive flows that drive a detonation or deflagration through a white dwarf, mapping realistic merger-phase initial conditions from the moving-mesh code AREPO and developing custom refinement strategies that make otherwise intractable runs affordable. He then post-processes the thermodynamic histories with the Torch nuclear reaction network to predict detailed nucleosynthetic yields, and builds Python-based analysis pipelines that turn raw simulation output into abundances and other observable signatures.
Much of his current effort centers on the double-degenerate channel, in which two white dwarfs merge — from helium-ignited sub-Chandrasekhar systems that detonate through a double- or quadruple-detonation cascade, to oxygen–neon and carbon–oxygen mergers near the Chandrasekhar mass. Earlier work constrained the near-Chandrasekhar remnant 3C 397, where his pure-deflagration models reproduced the neutron-rich ejecta measured in X-rays. Across these projects the goal is the same: to connect the microphysics of the explosion to what large telescopes such as NASA’s JWST and the JAXA/NASA XRISM mission actually observe, and to sharpen the picture of the progenitor channels realized in nature.
Current Projects
I perform 3D hydrodynamical simulations of helium-ignited binary white dwarf mergers using FLASH with adaptive mesh refinement (AMR), mapping merger-phase initial conditions from the moving-mesh code AREPO. A custom refinement strategy reduces the computational cost by roughly 4–5×.
The simulations reveal two distinct outcomes: a double detonation (D6) in which the secondary white dwarf survives intact, and a quadruple detonation in which helium and core detonations propagate to the secondary, destroying both white dwarfs — consistent with recent theoretical predictions for the dominant outcome of helium-ignited mergers. I also compute the nucleosynthetic yields for both models.
Building on the helium-ignited merger work, this project explores the explosion outcomes of oxygen–neon and carbon–oxygen white dwarf mergers in the double-degenerate channel, investigating the conditions under which these systems produce Type Ia supernovae. A first-authored paper is in preparation.
Past Projects
I developed 2D FLASH models of pure deflagration and delayed-detonation explosions and computed nucleosynthetic yields with the Torch nuclear network.
The work showed that a pure deflagration explosion best reproduces the observed neutron-rich X-ray abundances of 3C 397 measured by Suzaku. The results were published in MNRAS (2024) and presented at AAS 242 and APS New England.