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arXiv · 2104.03263

Analytical Solutions for Radiation-Driven Winds in Massive Stars II: The $\delta$-slow Regime

I. Araya·A. Christen·M. Curé·L. S. Cidale·R. O. J. Venero·C. Arcos·A. C. Gormaz-Matamala·M. Haucke·P. Escárate·H. Clavería
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Abstract

Accurate mass-loss rates and terminal velocities from massive stars winds are essential to obtain synthetic spectra from radiative transfer calculations and to determine the evolutionary path of massive stars. From a theoretical point of view, analytical expressions for the wind parameters and velocity profile would have many advantages over numerical calculations that solve the complex non-linear set of hydrodynamic equations. In a previous work, we obtained an analytical description for the fast wind regime. Now, we propose an approximate expression for the line-force in terms of new parameters and obtain a velocity profile closed-form solution (in terms of the Lambert $W$ function) for the $\delta$-slow regime. Using this analytical velocity profile, we were able to obtain the mass-loss rates based on the m-CAK theory. Moreover, we established a relation between this new set of line-force parameters with the known stellar and m-CAK line-force parameters. To this purpose, we calculated a grid of numerical hydrodynamical models and performed a multivariate multiple regression. The numerical and our descriptions lead to good agreement between their values.

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I. Araya, A. Christen, M. Curé, L. S. Cidale, R. O. J. Venero, C. Arcos, A. C. Gormaz-Matamala, M. Haucke, P. Escárate, H. Clavería. 2021-04-07. Analytical Solutions for Radiation-Driven Winds in Massive Stars II: The $\delta$-slow Regime. https://doi.org/10.1093/mnras/stab995

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