New self-consistent theoretical descriptions for mass-loss rates of O-type stars

¹ Instituto de Física y Astronomía, Universidad de Valparaíso. Av. Gran Bretaña 1111, Casilla 5030, Valparaíso, Chile
² Centro de Astrofísica, Universidad de Valparaíso. Av. Gran Bretaña 1111, Casilla 5030, Valparaíso, Chile
³ Centro Multidisciplinario de Física, Vicerrectoría de Investigación, Universidad Mayor, 8580745 Santiago, Chile
⁴ Departamento de Espectroscopía, Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata (UNLP), Paseo del Bosque S/N (B1900FWA), La Plata, Argentina
⁵ Instituto de Astrofísica de La Plata, CCT La Plata, CONICET-UNLP, Paseo del Bosque S/N (B1900FWA), La Plata, Argentina
⁶ Department of Astronomy, University of Geneva, Chemin Pegasi 51, 1290 Versoix, Switzerland
⁷ Astronomical Institute, Czech Academy of Sciences, Fričova 298, 251 65 Ondřejov, Czech Republic

^★ Corresponding authors: This email address is being protected from spambots. You need JavaScript enabled to view it. ; This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 18 December 2025
Accepted: 12 February 2026

Abstract

Context. Massive O-type stars lose a significant fraction of their mass through radiation-driven winds, a process that critically shapes their evolution and feedback into the interstellar medium. Accurate predictions of mass-loss rates (Ṁ) are essential for models of stellar structure and population synthesis.

Aims. We computed wind parameters for O-type stars using a self-consistent approach that couples the hydrodynamics of the wind with detailed calculations of the line acceleration. This approach follows the theory of radiation-driven stellar winds and, thus, allows us to derive mass-loss rate distributions for different atomic configurations of the stellar flux.

Methods. We used the TLUSTY code for stellar atmosphere models to compute tailored non-local thermodynamic equilibrium models; these models served as input radiation fields for the calculation of the force multiplier factor and the line-force parameters, for which we used the LOCUS code. These line-force parameters were then iteratively coupled with the HYDWIND code to solve the wind hydrodynamics. The procedure was repeated until convergence and applied across a grid of stellar parameters for three chemical configurations.

Results. We obtain self-consistent wind parameters for a broad set of O-type stellar models. The results show a systematic decrease in mass-loss rates with the inclusion of more elements in the radiation field, which is attributed to a strong effect on the UV region of the spectral energy distribution. As more elements are included, resulting in a larger number of spectral lines, the contribution from the UV diminishes, leading to lower mass-loss rates. We fitted three theoretical prescriptions for Ṁ using a Bayesian approach; this yielded Pearson correlation values greater than 0.92 for all three model grids. It also allowed for the estimation of the wind momentum-luminosity relationships for each of the grids, yielding results similar to those based on observations of O-type stars.