Model Stellar Atmospheres

In addition to the Tlusty source code and the necessary data, we provide some model atmospheres for various stellar parameters and of different sophistication (as far as explicit NLTE model atoms are concerned). We intend to increase the number and variety of available NLTE model atmospheres in the future.

The BSTAR2006 Grid

We have constructed a comprehensive grid of 1540 metal line-blanketed, NLTE, plane-parallel, hydrostatic model atmospheres for the basic parameters appropriate to B-type stars. The BSTAR2006 grid considers 16 values of effective temperatures, 15000 K <= Teff <= 30000 K with 1000K steps, 13 surface gravities, 1.75 <= log g <= 4.75 with 0.25 dex steps, 6 chemical compositions from metal-rich relative to the Sun to metal-free, a solar helium abundance, He/H=0.1 by number, and a microturbulent velocity of 2 km/s. The lower limit of log g for a given effective temperature is set by an approximate location of the Eddington limit. Additional model atmospheres for B supergiants (log g <= 3.0) have been calculated with a higher microturbulent velocity (10 km/s) and a surface composition that is enriched in helium and nitrogen, and depleted in carbon. The table lists the stellar parameters and chemical compositions included in the grid. There are about 270 model atmospheres per chemical composition (a few models close to the Eddington limit could not be converged at the higher metallicities).

Reference: Lanz, T., & Hubeny, I. 2007, ApJS, 169, 83 (Abstract) (PDF)

 Stellar Parameters   Chemical Compositions
 Key   Z / Zo   Key   Z / Zo
 BC   2    
 BG   1    
 BL   1 / 2    
 BS   1 / 5    
 BT   1 / 10    BZ   0

Each model is characterized by a unique filename root describing the parameters of the model, for example BG25000g275v10CN. The first letters indicate the composition, followed by the effective temperature, the gravity and the turbulent velocity. 'CN' is added for models with an altered surface composition. A suffix is added to describe the contents of a given file.

The grid is available in the form of several tar archive files containing different products for each chemical composition.

Spectral Energy Distributions; Rebinned SEDs for Cloudy
Detailed UV Spectra (90-320 nm)
Detailed Visible Spectra (320-1000 nm)

Main Model Atmosphere Files (for additional computations)
Model Atmosphere Summary Files
NLTE Departure Coefficients

Global model parameters are listed in the following tables:

Bolometric Corrections
Radiative Acceleration

Additional spectra in other wavelength ranges, with altered chemical compositions, or with different values of the microturbulent velocity can be readily computed using Synspec, requiring three input files (Main Model Atmosphere Files), and the necessary atomic data files (model atoms and the relevant linelists).

Last update: March 9, 2007