Multidimensional Modeling of Type I X-ray Bursts. I. Two-Dimensional Convection Prior to the Outburst of a Pure Helium Accretor

Abstract

We present multidimensional simulations of the early convective phase preceding ignition in a Type I X-ray burst using the low Mach number hydrodynamics code, MAESTRO. A low Mach number approach is necessary in order to perform long-time integration required to study such phenomena. Using MAESTRO, we are able to capture the expansion of the atmosphere due to large-scale heating while capturing local compressibility effects such as those due to reactions and thermal diffusion. We also discuss the preparation of one-dimensional initial models and the subsequent mapping into our multidimensional framework. Our method of initial model generation differs from that used in previous multidimensional studies, which evolved a system through multiple bursts in one dimension before mapping onto a multidimensional grid. In our multidimensional simulations, we find that the resolution necessary to properly resolve the burning layer is an order of magnitude greater than that used in the earlier studies mentioned above. We characterize the convective patterns that form and discuss their resulting influence on the state of the convective region, which is important in modeling the outburst itself.

47 pages including 18 figures; submitted to ApJ; A version with higher resolution figures can be found at http://astro.sunysb.edu/cmalone/research/pure_he4_xrb/ms.pdf

References in corpus (3)

• Models of Type I X-ray Bursts from GS 1826-24: A Probe of rp-Process Hydrogen Burning
• Low Mach Number Modeling of Type Ia Supernovae. II. Energy Evolution
• Low Mach number modeling of Type I X-ray burst deflagrations

Cited by in corpus (31)

• Thermonuclear burst oscillations
• Neutron star mass and radius measurements from atmospheric model fits to X-ray burst cooling tail spectra
• Equation of state constraints for the cold dense matter inside neutron stars using the cooling tail method
• Frontiers in Nuclear Astrophysics
• Nucleosynthesis in Type I X-ray Bursts
• Thermonuclear X-ray bursts
• Nuclear Physics of the Outer Layers of Accreting Neutron Stars
• Nuclear astrophysics: the unfinished quest for the origin of the elements
• Energy conservation and gravity waves in sound-proof treatments of stellar interiors: Part II Lagrangian constrained analysis
• Thermonuclear Bursts with Short Recurrence Times from Neutron Stars Explained by Opacity-Driven Convection
• Flame Propagation on the Surfaces of Rapidly Rotating Neutron Stars during Type I X-ray Bursts
• Angular momentum fluctuations in the convective helium shell of massive stars
• Detection of burning ashes from thermonuclear X-ray bursts
• Multidimensional Modeling of Type I X-ray Bursts. II. Two-Dimensional Convection in a Mixed H/He Accretor
• MAESTROeX: A Massively Parallel Low Mach Number Astrophysical Solver
• Low Mach Number Modeling of Convection in Helium Shells on Sub-Chandrasekhar White Dwarfs. I. Methodology
• Meeting the Challenges of Modeling Astrophysical Thermonuclear Explosions: Castro, Maestro, and the AMReX Astrophysics Suite
• On the dependence of X-ray burst rate on accretion and spin rate
• Model Atmospheres for X-ray Bursting Neutron Stars
• Nuclear-powered X-ray millisecond pulsars
• Dynamics of Laterally Propagating Flames in X-ray Bursts. I. Burning Front Structure
• Three-dimensional instability of flame fronts in type I X-ray bursts
• X-ray burst ignition location on the surface of accreting X-ray pulsars: Can bursts preferentially ignite at the hotspot?
• Toward Resolved Simulations of Burning Fronts in Thermonuclear X-ray Bursts
• Thermal convection in rotating spherical shells: temperature-dependent internal heat generation using the example of triple-$\alpha$ burning in neutron stars
• Thermonuclear (Type Ia) Supernovae and Progenitor Evolution
• Hydrodynamical simulations of proton ingestion flashes in Type I X-ray Bursts
• Effects of tangential velocity in the reactive relativistic Riemann problem
• The onset of low Prandtl number thermal convection in thin spherical shells
• On the Importance of the Convective Urca Process in 3D Simulations of a Simmering White Dwarf
• Modelling low Mach number stellar hydrodynamics with MAESTROeX