  Classical main-sequence chemically peculiar stars show light variability that
originates in surface abundance spots. In the spots, the flux redistribution
due to line (bound-bound) and bound-free transitions is modulated by stellar
rotation and leads to light variability. White dwarfs and hot subdwarfs may
also have surface abundance spots either owing to the elemental diffusion or as
a result of accretion of debris. We model the light variability of typical
white dwarfs and hot subdwarfs that results from putative surface abundance
spots. We show that the spots with radiatively supported iron overabundance may
cause observable light variability of hot white dwarfs and subdwarfs. Accretion
of debris material may lead to detectable light variability in warm white
dwarfs. We apply our model to the helium star HD 144941 and conclude that the
spot model is able to explain most of observed light variations of this star.
