2025/09/15 by K. Vitovský, M. Brož, Vitovský, Kristián +1
Biochemistry, Genetics and Molecular Biology · Health Professions · Medicine · #FOS: Physical sciences #Myofascial pain diagnosis and treatment #Solar and Stellar Astrophysics (astro-ph.SR) #Spine and Intervertebral Disc Pathology #Therapeutic Uses of Natural Elements
paper · pdf · doi:10.48550/arxiv.2509.12139
openalex publication_date 2025/09/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
We study dynamics of circumstellar discs, with a focus on the β Lyrae A binary system. This system with ongoing mass transfer has been extensively observed, using photometry, spectroscopy and interferometry. All these observations were recently interpreted using a radiation-transfer kinematic model. We modified the analytical Shakura-Sunyaev models for a general opacity prescription, and derived radial profiles of various quantities. These profiles were computed for the fixed accretion rate, M = 2× 10-5 M_\odot \rm yr-1, inferred from the observed rate of change of the binary period. More general models were computed numerically, using 1-dimensional radiative hydrodynamics, accounting for viscous, radiative as well as irradiation terms. The initial conditions were taken from the analytical models. To achieve the accretion rate, the surface density~Σ must be much higher (of the order of 104 \rm kg \rm m-2 for the viscosity parameter α= 0.1) than in the kinematic model. Viscous dissipation and radiative cooling in the optically thick regime lead to a high midplane temperature~T (up to 105 \rm K). The accretion disc is still gas pressure dominated with the opacity close to Kramers one. To reconcile temperature profiles with observations, we had to distinguish three different temperatures: midplane, atmospheric and irradiation. The latter two are comparable to observations (30000 to 12000 K). We demonstrate that the aspect ratio~H of 0.08 can be achieved in a hydrostatic equilibrium, as opposed to previous works considering the disc to be vertically unstable.