The light variations of HD 37776 as a result of the uneven surface distribution of helium and silicon

We calculate the uvby light curves of the helium-strong chemically peculiar (CP) star HD 37776. Assuming that the chemical peculiarity influences the monochromatic radiative flux due to mainly the bound-free processes and using the model of the surface distribution of helium and silicon on HD 37776, as derived from spectroscopy, we calculate the emergent fluxes for a series of its rotational phases. We show that it is possible to consistently simulate light curves of a chemically peculiar star and that the basic properties of variability of helium CP stars can be understood in terms of the model of spots with a peculiar chemical composition.