  Supernovae (SNe) are among the most intensely studied objects of modern
astrophysics, but due to their complex physical nature, theoretical models are
essential to understand better these exploding stars, as well as the properties
of the variation of the emitted radiation. One possibility for modeling SNe
light curves is the construction of a simplified semi-analytic model, which can
be used for getting order-of magnitude estimates of the SN properties. One of
the strongest simplification in most of these light curve models is the
assumption of the constant Thomson-scattering opacity that can be determined as
the average opacity of the ejecta. Here we present a systematic analysis for
estimating the average opacity in different types of core-collapse supernovae
(CCSNe) that can be used as the constant opacity of the ejecta in simplified
semi-analytic models. To use these average opacities self-consistently during
light curve (LC) fit we estimate their values from hydrodynamic simulations. In
this analysis we first generate MESA (Paxton et al. 2011, 2013, 2015, 2018)
stellar models with different physical parameters (initial mass, metallicity,
rotation), which determine the mass-loss history of the model star. Then we
synthesize SN LCs from these models with the SNEC hydrodynamic code (Morozova
et al. 2015) and calculate the Rosseland mean opacity in every mass element.
Finally, we compute the average opacities by integrating these Rosseland mean
opacities. As a result we find that the average opacities from our calculations
show adequate agreement with the opacities generally used in previous studies.
