New Hydrodynamic Solutions for Line-driven Winds of Hot Massive Stars Using the Lambert W-function

0548005 - ASÚ 2022 RIV US eng J - Journal Article
Gormaz-Matamala, A. C. - Curé, M. - Hillier, D. J. - Najarro, F. - Kubátová, Brankica - Kubát, Jiří
New Hydrodynamic Solutions for Line-driven Winds of Hot Massive Stars Using the Lambert W-function.
Astrophysical Journal. Roč. 920, č. 1 (2021), č. článku 64. ISSN 0004-637X. E-ISSN 1538-4357
Institutional support: RVO:67985815
Keywords : stellar winds * hydrodynamics * early-type stars
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 5.521, year: 2021
Method of publishing: Limited access
https://doi.org/10.3847/1538-4357/ac12c9

We use the non-LTE model-atmosphere code CMFGEN to numerically solve the radiative transfer equation in the stellar atmosphere and to calculate the radiative acceleration g (rad)(r). Under the assumption that the radiative acceleration depends only on the radial coordinate, we solve analytically the equation of motion by means of the Lambert W-function. An iterative procedure between the solution of the radiative transfer and the equation of motion is executed in order to obtain a final self-consistent velocity field that is no longer based on any beta-law. We apply the Lambert-procedure to three O supergiant stars (zeta Puppis, HD 165763, and alpha Cam) and discuss the Lambert solutions for the velocity profiles. It is found that, even without recalculation of the mass-loss rate, the Lambert-procedure allows the calculation of consistent velocity profiles that reduce the number of free parameters when a spectral fitting using CMFGEN is performed. Synthetic spectra calculated from our Lambert solutions show significant differences compared to the initial beta-law CMFGEN models. The results indicate the importance of consistent velocity profile calculation in the CMFGEN code and its use in a fitting procedure and interpretation of observed spectra.
Permanent Link: http://hdl.handle.net/11104/0324135