Multicolour Photometry of AM Her During 1994–96

Author: Kjurkchieva Diana  

Publisher: Springer Publishing Company

ISSN: 0004-640X

Source: Astrophysics and Space Science, Vol.262, Iss.4, 1998-05, pp. : 453-476

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Abstract

Multicolour photometry of the polar AM Her was obtained during 3 observational seasons (1994/95/96). The star was in its high state for most of the observations. It was in its low state in '96 April. It was established that these two states differ not only in the average light level but in the larger amplitudes of variations at low state than at high state. Moreover the energy distributions of the two states differ in the stronger dependence of the flux on  at high state than at low state. The Fourier analysis of the photometric data shows variability with the spectroscopic (orbital) period. The amplitudes of this variability in all colours are about two times bigger at low state than at high state. An attempt to explain the photometric behaviour of AM Her by a model of dominant emission of two hot spots at the magnetic poles of the white dwarf was made and the spot parameters were determined.