Sr v–vi line widths in hot white dwarf atmospheres

Abstract

ABSTRACT Missing Stark widths for 37 spectral lines of strontium ions (17 Sr v lines and 20 Sr vi lines) have been calculated using a quantum-mechanical method. Twenty-three spectral lines of Sr v have been recently discovered, for the first time, in the ultraviolet spectrum of the hot white dwarf RE 0503−289. This recent discovery prompts us to calculate the Stark widths of the new lines. These calculations can fill the lack of the data base STARK-B and can be used to investigate the observed spectra in such stars. To perform the line broadening calculations, preliminary structure and collision calculations have been carried out using the sequence of the University College London codes (superstructure, distorted wave, and jajom). Results for the 37 lines are provided for different electron temperatures and at density Ne = 1017 cm−3. These results will enter the STARK-B data base, which is a node of the Virtual Atomic and Molecular Data Center. We hope that the obtained results will be useful for the non-local thermodynamic equilibrium modelling of stellar atmospheres.