Hydrodynamic simulations of WD-WD mergers and the origin of RCB stars
arXiv:2404.06864 · doi:10.1093/mnras/stae2343
Abstract
We study the properties of double white dwarf (DWD) mergers by performing hydrodynamic simulations using the new and improved adaptive mesh refinement code Octo-Tiger. We follow the orbital evolution of DWD systems of mass ratio q=0.7 for tens of orbits until and after the merger to investigate them as a possible origin for R Coronae Borealis (RCB) type stars. We reproduce previous results, finding that during the merger, the Helium WD donor star is tidally disrupted within 20-80 minutes since the beginning of the simulation onto the accretor Carbon-Oxygen WD, creating a high temperature shell around the accretor. We investigate the possible Helium burning in this shell and the merged object's general structure. Specifically, we are interested in the amount of Oxygen-16 dredged-up to the hot shell and the amount of Oxygen-18 produced. This is critical as the discovery of very low Oxygen-16 to Oxygen-18 ratios in RCB stars pointed out the merger scenario as a favorable explanation for their origin. A small amount of hydrogen in the donor may help keep the Oxygen-16 to Oxygen-18 ratios within observational bounds, even if moderate dredge-up from the accretor occurs. In addition, we perform a resolution study to reconcile the difference found in the amount of Oxygen-16 dredge-up between smoothed-particle hydrodynamics and grid-based simulations.
arXiv comment32 pages, Accepted to MNRAS
References in corpus (37)
- Modules for Experiments in Stellar Astrophysics (MESA)
- Modules for Experiments in Stellar Astrophysics (MESA): Giant Planets, Oscillations, Rotation, and Massive Stars
- Modules for Experiments in Stellar Astrophysics (MESA): Binaries, Pulsations, and Explosions
- Modules for Experiments in Stellar Astrophysics (MESA): Convective Boundaries, Element Diffusion, and Massive Star Explosions
- Modules for Experiments in Stellar Astrophysics (MESA): Pulsating Variable Stars, Rotation, Convective Boundaries, and Energy Conservation
- A Multi-Code Analysis Toolkit for Astrophysical Simulation Data
- Resolving mixing in Smoothed Particle Hydrodynamics
- Very Large Excesses of 18O in Hydrogen-Deficient Carbon and R Coronae Borealis Stars: Evidence for White Dwarf Mergers
- THE MINIMUM MASS RATIO OF W URSAE MAJORIS BINARIES
- Three in one go: consequential angular momentum loss can solve major problems of CV evolution
- SNSPH: A Parallel 3-D Smoothed Particle Radiation Hydrodynamics Code
- Formation of Extremely Low-mass White Dwarfs in Double Degenerates
- Numerical Simulations of the Onset and Stability of Dynamical Mass Transfer in Binaries
- Equilibrium, Stability and Orbital Evolution of Close Binary Systems
- The Stability of Double White Dwarf Binaries Undergoing Direct Impact Accretion
- Nucleosynthesis during the Merger of White Dwarfs and the Origin of R Coronae Borealis Stars
- Numerical Methods for the Simulation of Dynamical Mass Transfer in Binaries
- Do R Coronae Borealis Stars Form from Double White Dwarf Mergers?
- Reproducing the observed abundances in RCB and HdC stars with post-double degenerate merger models - constraints on merger and post-merger simulations and physics processes
- Evolving R Coronae Borealis Stars with MESA
- Octo-Tiger: A New, 3D Hydrodynamic Code for Stellar Mergers that uses HPX Parallelisation
- Properties of the remnant disk and the dynamical ejecta produced in low-mass black hole-neutron star mergers
- R Coronae Borealis Stars are Viable Factories of Pre-solar Grains
- From Piz Daint to the Stars: Simulation of Stellar Mergers using High-Level Abstractions
- Modeling R Coronae Borealis Stars: Effects of He-Burning Shell Temperature and Metallicity
- The dawn of a new era for dustless HdC stars with GAIA eDR3
- Constructing Synchronously Rotating Double White Dwarf Binaries
- R Coronae Borealis Star Evolution: Simulating 3D Merger Events to 1D Stellar Evolution Including Large Scale Nucleosynthesis
- The role of dredge-up in double white dwarf mergers
- Stellar Mergers with HPX-Kokkos and SYCL: Methods of using an Asynchronous Many-Task Runtime System with SYCL
- A Comparison of Grid-Based and SPH Binary Mass-Transfer and Merger Simulations
- A Spectral Classification System for Hydrogen-deficient Carbon Stars
- From Merging Frameworks to Merging Stars: Experiences using HPX, Kokkos and SIMD Types
- R Coronae Borealis and dustless Hydrogen-deficient Carbon stars have different oxygen isotope ratios
- From Task-Based GPU Work Aggregation to Stellar Mergers: Turning Fine-Grained CPU Tasks into Portable GPU Kernels
- Performance Measurements within Asynchronous Task-based Runtime Systems: A Double White Dwarf Merger as an Application
- Simulating Stellar Merger using HPX/Kokkos on A64FX on Supercomputer Fugaku