PoWR - The Potsdam Wolf-Rayet Models

This WEB interface allows to inspect and download synthetic spectra for Wolf-Rayet stars. The spectra are calculated from PoWR model atmospheres which account for Non-LTE, spherical expansion and metal line blanketing. The models are described in Gräfener G., Koesterke L., Hamann W.-R.: 2002, Astron. Astrophys., 387, 244 and Hamann, W.-R., Gräfener: 2003, Astron. Astrophysics, 410, 993. The WN model grids presented via this WEB interface belong to the publication Hamann, W.-R., Gräfener: 2004, Astron. Astrophysics, 427, 697, where more details can be found. We expect that users of the PoWR spectra will give references to these papers.

Note that this homepage makes use of popup windows; a popup blocker prevents its proper operation. In case of problems please contact Wolf-Rainer Hamann (wrh@astro.physik.uni-potsdam.de).
This WEB interface has been developed by Daniel M. Hamann and Wolf-Rainer Hamann (2004).

Synthetic spectra

The following data are available for each model:
- Spectral Energy Distribution
  (emergent flux received at 10pc distance, low spectral resolution)
- Line spectrum in high resolution for different wavelength bands
  (optionally normalized or flux-calibrated)

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. The following grids are available yet:

Grid WNE WNL WC
log L / Lsun 5.3 5.3 5.3
vfinal [km/s] 1600 1000 2000
clumping D 4 4 10
Mass fraction
H 0 0.2 0
He 0.98 0.78 0.55
C 1E-4 1E-4 0.4
N 0.015 0.015 0
0 0 0 0.05
Fe 0.0014 0.0014 0.0016

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 (August 2012): The WNL grid has been re-calculated in 2012 and is now shown by default. Details of the new version are given here. The previous version of the WNL grid can still be accessed by choosing "WNL-2004" in the drop-down menu below.

New (May 2013): The WNE grid has been re-calculated in 2013 and is now shown by default. Details of the new version are given here. The previous version of the WNE grid can still be accessed by choosing "WNE-2004" in the drop-down menu below.

You can choose the model grid: