Creating and using large grids of precalculated model atmospheres for a rapid analysis of stellar spectra

¹ Environmental Physics Laboratory (EPHYSLAB), Facultad de Ciencias, Campus de Ourense, Universidad de Vigo, Ourense 32004, Spain
² Departamento de Física, Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Avenida Instituto Politécnico Nacional s/n, Edificio 9, Gustavo A. Madero, San Pedro Zacatenco, 07738 Ciudad de México, Mexico
e-mail: jzsargo@ipn.mx
³ Departamento de Física, Instituto Nacional de Investigaciones Nucleares (ININ), Carretera México-Toluca km. 36.5, La Marquesa, 52750 Ocoyoacac, Estado de México, Mexico
⁴ Universidad Iberoamericana, Prolongación Paseo de la Reforma 880, Alvaro Obregon, Lomas de Santa Fe, 01219 Ciudad de México, Mexico
⁵ Departamento de Ciencias Básicas, Universidad Autónoma Metropolitana-Azcapotzalco (UAM-A), Av. San Pablo 180, 02200 Ciudad de México, Mexico
⁶ Facultad de Ingeniería, Ciencias Físicas y Matemática, Universidad Central del Ecuador, Ciudadela Universitaria, Quito, Ecuador
⁷ Centro de Física, Universidad Central del Ecuador, Ciudadela Universitaria, Quito, Ecuador

Received: 29 March 2020
Accepted: 17 August 2020

Abstract

Aims. We present a database of 43 340 atmospheric models (∼80 000 models at the conclusion of the project) for stars with stellar masses between 9 and 120 M_⊙, covering the region of the OB main-sequence and Wolf-Rayet stars in the Hertzsprung-Russell diagram.

Methods. The models were calculated using the ABACUS I supercomputer and the stellar atmosphere code CMFGEN.

Results. The parameter space has six dimensions: the effective temperature T_eff, the luminosity L, the metallicity Z, and three stellar wind parameters: 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 (10 000−40 000 Å) regions. To facilitate comparison with observations, the synthetic spectra can be rotationally broadened using ROTIN3, by covering v sin i velocities between 10 and 350 km s⁻¹ with steps of 10 km s⁻¹.

Conclusions. We also present the results of the reanalysis of ϵ Ori using our grid to demonstrate the benefits of databases of precalculated models. Our analysis succeeded in reproducing the best-fit parameter ranges of the original study, although our results favor the higher end of the mass-loss range and a lower level of clumping. Our results indirectly suggest that the resonance lines in the UV range are strongly affected by the velocity-space porosity, as has been suggested by recent theoretical calculations and numerical simulations.