Colloquium on 7 August 2014
Rapid Photometry of Magnetic Cataclysmic Variable Stars

Details

Title: Rapid Photometry of Magnetic Cataclysmic Variable Stars
Speaker: Hannes Breytenbach
Date: Thursday, 7 August 2014
Time: 11:00 - 11:20
Venue: SAAO Auditorium

Abstract

Magnetic Cataclysmic Variables (mCVs) are semi-detached binary star systems consisting of a degenerate White Dwarf (WD) primary and a lower Main Sequence donor star. Material in these objects accretes from the donor star through a truncated disc before eventually becoming channelled in the innermost regions by the strong magnetic field. As such, mCVs, and the extreme physical conditions they command, offer a unique probe into the properties of magnetically confined, supersonic plasma flows. The rapid photometric variability observed in these objects is thought to originate mostly within the accretion column where the channelled flow of material impacts the surface of the WD. Of particular interest are the Quasi-Periodic Oscillations (QPOs), presumably generated by the radial oscillation of a shock front within the column. By studying such QPOs – their relative stability, orbital phase- and system state dependencies – one may gain insight into the geometry of the accretion flow and magnetic field of the host star. This work represents the systematic study of the optical variability of a large number of southern hemisphere Polars with the goal of better understanding how magnetism affects accretion.

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