Analytical solutions for radiation-driven winds in massive stars - II. The δ-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

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


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 δ-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.

Original languageEnglish
Pages (from-to)2550-2556
Number of pages7
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
StatePublished - 1 Jun 2021
Externally publishedYes


  • hydrodynamics
  • methods: analytical
  • stars: early-type
  • stars: mass-loss
  • stars: winds, outflows


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