Peculiarities of physical property distribution on the surface of CP Star HD182255

Abstract

The star HD182255 reveals spectral variability in rotation, irregular short-term variability, as well as long-term variations in the spectra. The He and Si abundances vary in antiphase. According to the theory, silicon accumulates in the regions between the poles, where the field lines are horizontal. Hence the observed behavior of He and Si may indicate the presence of magnetic field, where one of the poles passes through the central meridian in phase Φ = 0 as the star rotates. Given a general weakening of He over the entire surface, in Φ = 0 its abundance is higher, which may be linked with the presence of wind from the magnetic pole. The star definitely belongs to the He-w type. The study of the structure of the upper atmosphere based on the hydrogen line profiles shows that it varies over the years. Our estimates of the magnetic field from the Zeeman spectra are within the measurement errors. According to the spectroscopic characteristics the star can be considered weakly magnetic.