PoWR - The Potsdam Wolf-Rayet Models

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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.

Model atmospheres and synthetic spectra

The following data is available for each model:

Model parameters and organisation

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.

Wolf-Rayet model grids

log LvfinalDmax XH XHeXC XNXO XNeXFe
[Lsun][km/s] mass fractions
Galactic Metallicity
WNEDetails5.316004-0.981.0E-40.015--1.4E-3
WNL-H20Details5.3100040.20.781.0E-40.015--1.4E-3
WNL-H50Details5.3100040.50.481.0E-40.015--1.4E-3
WCDetails5.3200010-0.550.4-0.05-1.6E-3
LMC Metallicity
WNEDetails5.3160010-0.9957.0E-54.0E-3--7.0E-4
WNL-H20Details5.31000100.20.7957.0E-54.0E-3--7.0E-4
WNL-H40Details5.31000100.40.5957.0E-54.0E-3--7.0E-4
WCDetails5.3200010-0.550.4-0.051.0E-37.0E-4
SMC Metallicity
WNEDetails5.3160010-0.9982.5E-51.5E-3--3.0E-4
WNL-H20Details5.31600100.20.7982.5E-51.5E-3--3.0E-4
WNL-H40Details5.31600100.40.5982.5E-51.5E-3--3.0E-4
WNL-H60Details5.31600100.60.3982.5E-51.5E-3--3.0E-4

"Double beta-law", see WR model parameter details dropdown below

You can choose the WR model grid:

WR model parameter details

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.

Recent Updates

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.

OB model grids

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).

Tlog g log MDmax XH XHeXC XNXO XMgXSi XPXS XFe
[kK][cgs][Msun/yr] mass fractions
Galactic Metallicity
OB-IDetails15…562.0…4.4-7100.7380.2582.4E-36.9E-45.7E-36.9E-46.7E-45.8E-63.1E-41.2E-3
LMC Metallicity
LMC-OB-IDetails15…502.0…4.4-7100.7380.2584.7E-47.8E-52.6E-32.1E-43.2E-42.9E-61.5E-47.0E-4
SMC Metallicity
SMC-OB-IDetails15…502.0…4.4low100.7380.2612.1E-43.3E-51.1E-39.9E-51.3E-48.3E-74.4E-53.5E-4
SMC-OB-IIDetails15…502.0…4.4high100.7380.2612.1E-43.3E-51.1E-39.9E-51.3E-48.3E-74.4E-53.5E-4

You can choose the OB model grid:

OB model parameter details
Original web interface developed by Daniel M. Hamann and Wolf-Rainer Hamann in 2004. PHP-based rework by Andreas Sander (2016).
In case of problems with the PoWR website please contact Wolf-Rainer Hamann (wrh@astro.physik.uni-potsdam.de).
Astrophysics at the University of Potsdam -- University of Potsdam -- Imprint