New NLTE OB Star Grid ("NLTE-OBGRID")

Ivan Hubeny has updated the TLusty OB NLTE model SED grids of Lanz & Hubeny (2003) and Lanz & Hubeny (2007) using a more complete hydrogen atom to produce more realistic IR flux predictions. In particular, the new NLTE spectra have a much better description of line confluences and of the contribution to the opacity in very high series members. In addition, there are improvements in the treatment of the hydrogen and He II continua from high levels, inclusion of more scattering opacity sources, and updates to the physics of level dissolution. Each model has 29957 points at constant spectral resolution of R=5000 and a micro-turbulent velocity of 2 km/s. The Asplund et al. (2009) element abundances are used for computing the spectra. The grid contains 1082 model pairs of spectra and continua and covers effective temperature Teff in the range 15,000-55,000 K and surface gravity log(g) between 1.75 and 4.75, with steps of 0.25. The steps in Teff are 1,000 K between 15,000 and 29,000 K and 2,500 K between 30,000 and 55,000 K. As Teff rises, more of the unstable lower surface gravities are omitted. There are five metallicity values log Z=[M/H] of 0.301, 0.000, -0.301, -0.70, and -1.00, which correspond to Z=2, 1, 0.5, 0.2, and 0.1, where Z=1 is the solar value. The continuum spectra have a coarser wavelength scale than the spectra.