Hydrodynamické simulace cirkumstelárních disků

Vitovský, Kristián

In this work, we study the dynamics of circumstellar discs, with a focus on the β Lyræ A binary system. This system has been extensively observed by photometry, spectroscopy and interferometry. All these observations were recently interpreted by a radiation-transfer kinematic model [Brož et al. 2021]. In order to apply dynamical models, we first review the theory of steady-state viscous accretion discs, including the α-parametrisation of the viscosity. We modified the analytical models [Shakura and Sunyaev 1973] for a general opacity prescription, κ = κ0ρA TB , and derived radial profiles of various quantities (Σ, T, H). The profiles were computed for the accretion rate ̇M = 2·10−5 M⊙ yr−1 , inferred from the observed rate of change of the binary period. To achieve this rate, the surface densities Σ must be much higher (of the order of 10000 kg m−2 for α = 0.1) than in the kinematic model. Viscous dissipation and radiative cooling in the optically thick regime lead to high mid-plane temperatures. The disk is still gas pressure dominated. More general models were computed numerically. We used 1-dimensional radiative hydrodynamic models [Chrenko et al. 2017], accounting for viscous, radiative as well as irradiation terms. The initial conditions were taken from the analytical models. The simulations achieved a...

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