INFLUENCE OF PECULARITY EFFECT ON BALMER DISCONTINUITY IN THE ATMOSPHERES OF MAGNETIC CP STARS

Abstract

On the basis of 10 color photometric materials Balmer jumps were determined for different magnetic stars taking into account the peculiarity effect - the presence of a strong magnetic eld (Be> 1000 gauss) and chemical anomalies in the spotted areas of the stars studied. The influences of chemical anomalies and the magnetic field on the structure and physical conditions, including
Balmer jumps, in the atmospheres of MCP stars are analyzed. It was found that due to an excess (for 2-5 orders) of peculiar elements (Si, Cr, Sr, Eu, Nd, etc.), energy absorption by the lines of these elements (blanketing effect) occurs in spotted regions of the atmosphere of these stars. Thus, chemical anomalies owing to additional blanketing effect, have an essential influence
on the occurrence of additional source of opacity and correspondingly on the  change of continuum spectrum in the region of the Balmer discontinuity. The magnetic field makes some contributions to the distribution of pressure (P = Pg + Pe), temperature and other parameters, as well as Zeeman effect leads to the strengthening blanketing effect with all associated effects. It is concluded
that the decrease in the Balmer jump mainly depends on the spectral (P) and photometric indices (Z,a) of the of peculiarity and the intensity of the magnetic field of the studied MCP stars.