Creating and Using Large Grids of Pre-calculated Model Atmospheres for Rapid Analysis of Stellar Spectra

Abstract

We present a database of 45,000 atmospheric models (which will become 80,000 models by the end of the project) with stellar masses between 9 and 120 ${\text{M}}_{ \odot }$, covering the region of the OB main sequence and W-R stars in the H–R diagram. The models were calculated using the ABACUS I supercomputer and the stellar atmosphere code CMFGEN. The parameter space has 6 dimensions: the effective temperature T_eff, the luminosity L, the metallicity Z, and three stellar wind parameters, namely the exponent β, the terminal velocity V_∞, and the volume filling factor F_cl. For each model, we also calculate synthetic spectra in the UV (900–2000 Å), optical (3500–7000 Å), and near IR (10000–30000 Å) regions. To facilitate comparison with observations, the synthetic spectra were rotationally broaden using ROTIN3, by covering v sin i velocities between 10 and 350 km/s⁻¹ with steps of 10 km/s⁻¹, resulting in a library of 1 575 000 synthetic spectra. In order to demonstrate the benefits of employing the databases of pre-calculated models, we also present the results of the re-analysis of ε Ori by using our grid.