2025/02/07 by R. G. Rast, Rina G. Rast, C. E. Jones +7 · 1 voice · 3 citations
Engineering · Physics and Astronomy · #Astrophysical Phenomena and Observations #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #Mechanics and Biomechanics Studies #Pulsars and Gravitational Waves Research #Solar and Stellar Astrophysics (astro-ph.SR) #astro-ph.HE #astro-ph.SR
paper · pdf · doi:10.48550/arxiv.2502.04705
openalex publication_date 2025/02/07 · arxiv published 2025/02/07 · arxiv updated 2025/02/07 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
We examine Be star discs in highly eccentric Be/X-ray systems. We use a three-dimensional smoothed particle hydrodynamics (SPH) code to model the structure of the Be star disc and investigate its interactions with the secondary star over time. We use system parameters consistent with the eccentric, short-period (P ≈ 16 d) Be/X-ray binary A0538-66 as the basis for our models. We explore a range of system geometries by incrementally varying the misalignment angle of the neutron star's orbital plane with respect to the primary star's equatorial plane to cover a complete range from coplanar prograde to coplanar retrograde. For all simulations, we follow the evolution of the disc's total mass and angular momentum as well as the average eccentricity and inclination with respect to the equatorial planes of both the primary and secondary. We also determine the neutron star accretion rates. We find that the high eccentricity of the binary orbit causes all calculated disc parameters to vary with orbital phase in all models. The amplitude of these variations is negatively correlated with misalignment angle for models with misalignment angles less than 90°, and positively correlated for models with misalignment angles greater than 90°. Accretion rates are affected by the number of particles the neutron star interacts with as well as the length of the interaction time between the particles and the neutron star. We find that accretion rates are largest for models with misalignment angles less than 90°, and smaller for models with those greater than 90°.