The light variability of the helium strong star HD 37776 as a result of its inhomogeneous elemental surface distribution

TL;DR

This study models the light variability of the helium-strong star HD 37776 based on inhomogeneous surface chemical distributions, successfully reproducing observed light curves and explaining the star's variability.

Contribution

The paper presents a model linking surface chemical inhomogeneities to light variability in HD 37776, aligning simulated and observed light curves.

Findings

Chemical peculiarity affects monochromatic radiative flux mainly through bound-free processes.

Simulated light curves match observed ones in shape and amplitude.

Surface chemical spots can explain the star's variability.

Abstract

We simulate light curves of the helium strong chemically peculiar star HD 37776 assuming that the observed periodic light variations originate as a result of inhomogeneous horizontal distribution of chemical elements on the surface of a rotating star. We show that chemical peculiarity influences the monochromatic radiative flux, mainly due to bound-free processes. Using the model of the distribution of silicon and helium on HD 37776 surface, derived from spectroscopy, we calculate a photometric map of the surface and consequently the uvby light curves of this star. Basically, the predicted light curves agree in shape and amplitude with the observed ones. We conclude that the basic properties of variability of this helium strong chemically peculiar star can be understood in terms of the model of spots with peculiar chemical composition.