The relative simplicity of White Dwarfs (WDs) is leveraged in a wide range of astrophysical contexts from cosmochronology to the history of chemical enrichment in a galaxy. WDs are also used as spectrophotometric standards by many major observatories. Thier usefulness however, hinges on accurately determining their fundamental parameters: temperature and mass. Our ability to accurately infer these parameters relies in turn, on the fidelity of our model atmosphere calculations.

 

The advent of large photometric data sets from surveys like Gaia and Pan-STARRS has enabled a cross-comparison of fundamental parameter determinations made using different techniques. The analyses yield concerning systematic discrepancies in masses and temperatures inferred using photometry compared to those obtained using spectroscopy. Additionally, spectroscopic fits to individual Balmer lines in the same star often return wildly varying results. The evidence suggests that there are inaccuracies in our treatment of Stark broadening in the Hydrogen line profile calculations used in model atmospheres.

 

These line profile calculations have not been substantially updated since the 1970s despite the fact that there have been many advancements made in line shape theory since then. We now have access to two new line shape codes (simulation and analytic) which have been developed over the course of several years (Thomas Gomez '17) that reflect the current state of the art. I will discuss the preliminary work we've done to incorporate a set of new analytic line shape calculations into Hydrogen (DA) WD model atmospheres, and why this prompted a return to the simulation code. I will then detail a series of improvements we made to the simulation code. The code is now capable of producing profiles which are clean and accurate enough for use in model atmospheres.