Analytical solutions for radiation-driven winds in massive stars. II: The delta-slow regime

CURÉ, M.; VENERO, R. O. J.; ARAYA, I.; CIDALE, L.; HAUCKE, M.; CHRISTEN, A. ; CLAVERÍA, H.; ARCOS, C.

Antofagasta

Congreso; XVI Latin American Regional Meeting; 2020

International Astronomical Union

Accurate mass-loss rates and terminal velocities from line-driven winds are important to obtain synthetic spectra from radiative transfer calculations. From a theoretical point of view, analytical expressions forthe wind parameters and velocity profile would have many advantages over numerical calculations, that solve the complex non-linear set of hydrodynamic equations. In our previous work, we obtained an analytic description for the fast wind regime. Now, we propose a new analytical expression for the line-force term and obtain a velocity profile closed-form solution for the δ-slow regime. Using this analytical expression, we describe a methodology to obtain the mass-loss rates. Moreover, we establish a relation between our line-force term with the known stellarand m-CAK line force parameters. To this purpose, we calculate a grid of numerical hydrodynamical models and perform a multivariate multiple regression. The numerical and analytical descriptions lead to almost the same synthetic spectra.