The common envelope phase plays a crucial role in the evolution of binary systems, transforming wide binaries into close orbits, with significant implications for the formation of compact object binaries such as neutron star-neutron star and black hole-neutron star systems. The outcome depends on whether the red giant successfully ejects its envelope or fails to do so, influencing the final system configuration. This phase also allows for the possible existence of exotic objects like Thorne-Żytkow hybrid stars.
However, fully resolving common envelope evolution in 3D hydrodynamic simulations is computationally expensive, requiring long timescales to capture the inspiral process. To address this, I developed a 1D Python-based inspiral model coupled with the MESA stellar evolution code to simulate the interaction between a red giant and a neutron star, enabling efficient exploration of envelope ejection and system outcomes.
Type Ia Supernova:
Head-On Collisions of White Dwarfs
A defining characteristic of Type Ia supernovae is the presence of nickel and other heavy elements, which can be produced during the collision of white dwarf stars. Using the GRMHD code COSMOS++ at Lawrence Livermore National Laboratory, we conducted high-resolution simulations to analyze the nuclear energy release and heavy element synthesis in these events. Our study focused on running resolution tests to ensure convergence in the predicted nuclear energy yield and nickel production, providing insights into the explosive outcomes of white dwarf collisions.
Head-On Collisions of White Dwarfs
A defining characteristic of Type Ia supernovae is the presence of nickel and other heavy elements, which can be produced during the collision of white dwarf stars. Using the GRMHD code COSMOS++ at Lawrence Livermore National Laboratory, we conducted high-resolution simulations to analyze the nuclear energy release and heavy element synthesis in these events. Our study focused on running resolution tests to ensure convergence in the predicted nuclear energy yield and nickel production, providing insights into the explosive outcomes of white dwarf collisions.
Active Galatic Nuclei (AGN) Accretion Disk Feedback
When the temperature of the interstellar medium is low, it allows for the gas to condense and contract to its gravity leading to the formation of stars. However, we do not observe the expected rate of star formations which leads one to consider other heating sources such as feedback from accretion disks for supermassive black holes.
However, it is difficult to achieve enough resolutions to resolve the behavior surrounding a black hole and its feedback outwards at scales of kpc.
When the temperature of the interstellar medium is low, it allows for the gas to condense and contract to its gravity leading to the formation of stars. However, we do not observe the expected rate of star formations which leads one to consider other heating sources such as feedback from accretion disks for supermassive black holes.
However, it is difficult to achieve enough resolutions to resolve the behavior surrounding a black hole and its feedback outwards at scales of kpc.
Binary Neutron Star Mergers: Subgrid Model
Numerical simulations of binary neutron star (BNS) mergers have been extensively developed to study the evolution of magnetic fields. During the merger, a significant magnetic field amplification occurs, primarily driven by the Kelvin-Helmholtz instability. However, current direct numerical simulations (DNS) lack the resolution needed to fully capture this instability due to extreme computational demands.
Numerical simulations of binary neutron star (BNS) mergers have been extensively developed to study the evolution of magnetic fields. During the merger, a significant magnetic field amplification occurs, primarily driven by the Kelvin-Helmholtz instability. However, current direct numerical simulations (DNS) lack the resolution needed to fully capture this instability due to extreme computational demands.
To address this limitation, I aim to develop a subgrid model that accurately represents these small-scale magnetic field dynamics while being integrated into DNS. This approach will reduce computational costs while extending simulation times, allowing for more frequent studies of magnetic field geometry, strength, and the nuclear equation of state in neutron stars. Ultimately, this work aims to make high-fidelity BNS merger simulations more efficient and accessible for astrophysical investigations.