This WEB interface allows to inspect and download synthetic spectra for Wolf-Rayet and OB stars. The spectra are calculated from PoWR model atmospheres which account for Non-LTE, spherical expansion and metal line blanketing.
The models are arranged in different Model Grids. Each model grid is characterized by a set of common parameters, such as stellar luminosity, terminal wind velocity, clumping contrast, and chemical composition. For Wolf-Rayet stars of the nitrogen subclass (WN) there are grids of hydrogen-free models (WNE) and of models with a specified mass fraction of hydrogen (WNL). The iron-group and total CNO mass fractions correspond to the metallicity of the Galaxy, the Large Magellanic Cloud (LMC), or the Small Magellanic Cloud (SMC), respectively.
‡ "Double beta-law", see WR model parameter details dropdown below
Each grid has a two-dimensional parameter space, namely the stellar temperature T and the "transformed radius" Rt. The latter is a function of the mass-loss rate and the stellar radius. Thanks to an approximate scaling invariance of WR atmospheres, the same model spectrum can be applied to stars with different luminosities, but same T and Rt. When doing so, the absolute fluxes must be scaled proportional to L, the radius R proportional to L1/2, and the mass-loss rate proportional to L3/4.
New (Sept. 2016): The WNE grid has been re-calculated in 2016; this latest version is shown by default. The previous version of the WNE grid can still be accessed by choosing "WNE-2013" in the drop-down menu below.
New (Oct. 2016): The WNL grid has been re-calculated in 2016; this latest version is shown by default. The previous version of the WNL grid can still be accessed by choosing "WNL-2012" in the drop-down menu below.
New (Oct. 2016): The WNL-H50 grid has been re-calculated in 2016; this latest version is shown by default. The previous version of the WNL-H50 grid can still be accessed by choosing "WNL-H50-2013" in the drop-down menu below.
Grids of models for O- and B-type stars are provided for solar metallicity, for a metallicity of 1/2 solar as appropriate for the Large Magellanic Cloud (LMC), and for a metallicity of 1/7 solar as appropriate for the Small Magellanic Cloud (SMC), respectively.
Each grid has a two-dimensional parameter space, namely the stellar temperature T and the surface gravity ggrav. The grid resolution is 1 kK for the stellar temperature and 0.2dex for the surface gravity, log g. For each grid model with given T and log g, the luminosity and stellar mass are derived from the stellar evolution models published by Brott et al. (2011).
The mass-loss rate for the grids with solar and with LMC metallicity is set to 10-7 M yr-1 throughout. For SMC metallicity, two grids with different mass loss are provided. The grid with a low mass-loss rate are calculated with log Q = -13.0, while the grids with a high mass-loss rate are calculated with log Q = -12.0. (See the button "OB model parameter details" below for the definition of Q.)
The OB model grids will be described in more detail in a forthcoming paper (Hainich et al. 2018).
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