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### Model atmospheres and synthetic spectra

The following data is available for each model:

### Model parameters and organisation

## Wolf-Rayet model grids

### Recent Updates

## OB model grids

### Recent Updates

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.

- 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) - Atmosphere stratification

(incl. electron temperature, density, optical depth, etc.) - Colors and ionizing photons

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.

log L | v_{final} | D_{max} |
X_{H} |
X_{He} | X_{C} |
X_{N} | X_{O} |
X_{Ne} | X_{Fe} |
|||
---|---|---|---|---|---|---|---|---|---|---|---|---|

[L_{sun}] | [km/s] | mass fractions | ||||||||||

Galactic Metallicity | ||||||||||||

WNE | Details | 5.3 | 1600 | 4 | - | 0.98 | 1.0E-4 | 0.015 | - | - | 1.4E-3 | |

WNL-H20 | Details | 5.3 | 1000 | 4 | 0.2 | 0.78 | 1.0E-4 | 0.015 | - | - | 1.4E-3 | |

WNL-H50 | Details | 5.3 | 1000 | 4 | 0.5 | 0.48 | 1.0E-4 | 0.015 | - | - | 1.4E-3 | |

WC | Details | 5.3 | 2000 | 10 | - | 0.55 | 0.4 | - | 0.05 | - | 1.6E-3 | |

LMC Metallicity | ||||||||||||

WNE | Details | 5.3 | 1600 | 10 | - | 0.995 | 7.0E-5 | 4.0E-3 | - | - | 7.0E-4 | |

WNL-H20 | Details | 5.3 | 1000 | 10 | 0.2 | 0.795 | 7.0E-5 | 4.0E-3 | - | - | 7.0E-4 | |

WNL-H40 | Details | 5.3 | 1000 | 10 | 0.4 | 0.595 | 7.0E-5 | 4.0E-3 | - | - | 7.0E-4 | |

WC | Details | 5.3 | 2000 | 10 | - | 0.55 | 0.4 | - | 0.05 | 1.0E-3 | 7.0E-4 | |

SMC Metallicity | ||||||||||||

WNE | Details | 5.3 | 1600^{‡} | 4 | - | 0.998 | 2.5E-5 | 1.5E-3 | - | - | 3.0E-4 | |

WNL-H20 | Details | 5.3 | 1600^{‡} | 4 | 0.2 | 0.798 | 2.5E-5 | 1.5E-3 | - | - | 3.0E-4 | |

WNL-H40 | Details | 5.3 | 1600^{‡} | 4 | 0.4 | 0.598 | 2.5E-5 | 1.5E-3 | - | - | 3.0E-4 | |

WNL-H60 | Details | 5.3 | 1600^{‡} | 4 | 0.6 | 0.398 | 2.5E-5 | 1.5E-3 | - | - | 3.0E-4 |

^{‡} "Double beta-law", see *WR model parameter details* dropdown below

WR model parameter details
▼

Each grid has a two-dimensional parameter space,
namely the stellar temperature T and the
"transformed radius" R_{t}. 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 R_{t}. When doing so, the absolute
fluxes must be scaled proportional to L, the radius R proportional to L^{1/2}, and the
mass-loss rate proportional to L^{3/4}.

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.

Bug warning (Feb. 2021): The H I Paschen line at about 8502 Angstroem (transition 3 - 16) appears shifted redwards by 2.4 Angstroem in all model spectra due to a mistake in the atomic data.

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
g_{grav}. 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, grids with different mass loss
are provided, based on different log Q values. (See the button "OB
model parameter details" below for the definition of Q.)

The OB model grids are described in more detail in Hainich et al. (2019).

T | log g | log M | log Q | D_{max} |
X_{H} |
X_{He} | X_{C} |
X_{N} | X_{O} |
X_{Mg} | X_{Si} |
X_{P} | X_{S} |
X_{Fe} |
|||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|

[kK] | [cgs] | [M_{sun}/yr] | mass fractions | ||||||||||||||

Galactic Metallicity | |||||||||||||||||

OB-I | Details | 15…56 | 2.0…4.4 | -7 | 10 | 0.738 | 0.258 | 2.4E-3 | 6.9E-4 | 5.7E-3 | 6.9E-4 | 6.7E-4 | 5.8E-6 | 3.1E-4 | 1.2E-3 | ||

LMC Metallicity | |||||||||||||||||

LMC-OB-I | Details | 15…50 | 2.0…4.4 | -7 | 10 | 0.738 | 0.258 | 4.7E-4 | 7.8E-5 | 2.6E-3 | 2.1E-4 | 3.2E-4 | 2.9E-6 | 1.5E-4 | 7.0E-4 | ||

SMC Metallicity | |||||||||||||||||

SMC-OB-I | Details | 15…50 | 2.0…4.4 | moderate | -13.0 | 10 | 0.738 | 0.261 | 2.1E-4 | 3.3E-5 | 1.1E-3 | 9.9E-5 | 1.3E-4 | 8.3E-7 | 4.4E-5 | 3.5E-4 | |

SMC-OB-II | Details | 15…50 | 2.0…4.4 | high | -12.0 | 10 | 0.738 | 0.261 | 2.1E-4 | 3.3E-5 | 1.1E-3 | 9.9E-5 | 1.3E-4 | 8.3E-7 | 4.4E-5 | 3.5E-4 | |

SMC-OB-III | Details | 15…50 | 2.0…4.4 | low | -14.0 | 10 | 0.738 | 0.261 | 2.1E-4 | 3.3E-5 | 1.1E-3 | 9.9E-5 | 1.3E-4 | 8.3E-7 | 4.4E-5 | 3.5E-4 |

OB model parameter details
▼

New (Aug. 2019): The grid SMC-OB-III (low mass-loss rates) has been added.

Bug warning (Feb. 2021): The H I Paschen line at about 8502 Angstroem (transition 3 - 16) appears shifted redwards by 2.4 Angstroem in all model spectra due to a mistake in the atomic data.

Bug warning (Feb. 2021): The S IV resonance line in the UV at 1062 - 1073 Angstroem is missing in all OB-type model spectra due to a mistake in the atomic data.