  Accurately measuring the masses of white dwarf stars is crucial in many
astrophysical contexts (e.g., asteroseismology and cosmochronology). These
masses are most commonly determined by fitting a model atmosphere to an
observed spectrum; this is known as the spectroscopic method. However, for
cases in which more than one method may be employed, there are well known
discrepancies between masses determined by the spectroscopic method and those
determined by astrometric, dynamical, and/or gravitational-redshift methods. In
an effort to resolve these discrepancies, we are developing a new model of
hydrogen in a dense plasma that is a significant departure from previous
models. Experiments at Sandia National Laboratories are currently underway to
validate these new models, and we have begun modifications to incorporate these
models into stellar-atmosphere codes.
