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 OSTAR2002 Grid

We have constructed a comprehensive grid of 690 metal line-blanketed, NLTE, plane-parallel, hydrostatic model atmospheres for the basic parameters appropriate to O-type stars. The OSTAR2002 grid considers 12 values of effective temperatures, 27500 K <= Teff <= 55000 K with 2500K steps, 8 surface gravities, 3.0 <= log g <= 4.75 with 0.25 dex steps, and 10 chemical compositions, from metal-rich relative to the Sun to metal-free. The lower limit of log g for a given effective temperature is set by an approximate location of the Eddington limit. The selected chemical compositions have been chosen to cover a number of typical environments of massive stars: the galactic center, the Magellanic Clouds, Blue Compact Dwarf galaxies like I Zw 18, and galaxies at high redshifts. The table lists the stellar parameters and chemical compositions included in the grid. There are 69 model atmospheres per composition. We have assumed a solar helium abundance, He/H=0.1 by number, and a microturbulence velocity, Vt = 10 km/s.

Reference: Lanz, T., & Hubeny, I. 2003, ApJS, 146, 417 (Abstract) (PDF)

 Stellar Parameters   Chemical Compositions
 Key   Z / Zo   Key   Z / Zo
 C   2   V   1 / 30
G   1   W   1 / 50
L   1 / 2   X   1 / 100
S   1 / 5   Y   1 / 1000
T   1 / 10   Z   0

Each model is characterized by a unique filename root describing the parameters of the model, for example G35000g400v10. The first letter indicates the composition, followed by the effective temperature, the gravity and the turbulent velocity. 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 (90-200 nm)
Detailed Visible Spectra (300-750 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
Ionization Fluxes
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: January 30, 2003