Krticka, J., Mikulasek, Z., Zverko, J., Ziznovsky, J.
Image & caption:
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Image caption::
The location of the calculated photometric spots on the star's surface in the u colour. We plot the smoothed flux emergent from the individual surface elements calculated using the observed surface distribution of helium and silicon derived by Khokhlova et al. (2000) in magnitudes. Here we do not include the limb darkening.
Description:
Periodic light variations are a common feature observed in the magnetic chemically peculiar (CP) stars. 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.
Reference:
Astronomy and Astrophysics, Volume 470, Issue 3, August II 2007, pp.1089-1098
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