  Our preliminary results from laboratory experiments studying white dwarf (WD)
photospheres show a systematic difference between experimental plasma
conditions inferred from measured H$\beta$ absorption line profiles versus
those from H$\gamma$. One hypothesis for this discrepancy is an inaccuracy in
the relative theoretical line profiles of these two transitions. This is
intriguing because atmospheric parameters inferred from H Balmer lines in
observed WD spectra show systematic trends such that inferred surface gravities
decrease with increasing principal quantum number, $n$. If conditions inferred
from lower-$n$ Balmer lines are indeed more accurate, this suggests that
spectroscopically determined DA WD masses may be greater than previously
thought and in better agreement with the mean mass determined from
gravitational redshifts.
