Heavy‐element abundance patterns in hot DA white dwarfs

We present a series of systematic abundance measurements for 25 hot DA white dwarfs in the temperature range ∼20 000‐110 000 K, based on far-ultraviolet spectroscopy with the Space Telescope Imaging Spectrograph (STIS)/Goddard High Resolution Spectrograph (GHRS) onboard Hubble Space Telescope, IUE and FUSE. Using our latest heavy-element blanketed non-local thermodynamic equilibrium (non-LTE) stellar atmosphere calculations we have addressed the heavy-element abundance patterns, making completely objective measurements of abundance values and upper limits using a χ 2 fitting technique to determine the uncertainties in the abundance measurements, which can be related to the formal upper limits in those stars