New Carbon II Spectral Line Shapes for Fitting Hot DQ White Dwarf Stars

Hot DQ white dwarf stars are hypothesized to have recently undergone double degenerate (D-D) mergers, making them failed Type Ia Supernovae. Estimates of the mass and temperature of these stars can help constrain the D-D merger rate of our galaxy, but rely heavily on the dominant Carbon II atomic line shapes used in their spectral fits. Previous studies attempting to determine these parameters use line shapes with invalid approximations in the regimes of white dwarf atmospheres. By using a semi-classical simulation method to compute the theoretical Carbon II line shapes, the spectral fits are expected to yield more accurate results. These new line shapes will be validated with data from the White Dwarf Photosphere Experiment on the Sandia Z Machine, and incorporated into synthetic spectra to fit Hot DQ white dwarf spectra.