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X10: a magnetic cataclysmic variable with pole-switching accretion

  • Author / Creator
    Hattawi, Asma
  • Cataclysmic variables (CVs) are binary stellar systems with a white dwarf (WD) and a companion star that is losing mass to the WD. When the magnetic field of the WD is strong enough, the accreting matter follows its magnetic field lines then falls near a magnetic pole. This leads to emission of radiation including X-rays. I analyzed Chandra X-ray data of the magnetic CV X10 in the star cluster 47 Tucannae. Analysis of the system’s X-ray light curves shows a 4.185 ± 0.038 hour modulation, interpreted as the white dwarf (WD) spin period. The modulation also shows phase shifts around ∼ 165 degrees, which I interpret as a result of the accretion flow switching its trajectory between regions near two opposite WD magnetic poles. This implies a possible asynchronism between the WD spin and binary orbital periods. To investigate the two-accretion region scenario, I roughly constrained the system’s geometry by simulating theoretical X-ray light curves and comparing them to observations. To investigate the degree of asynchronism, I constrained the orbital period of the system by analyzing the envelope patterns in the X-ray light curves, resulting in a range of possible orbital periods from ≈ 4.26 to ≈ 4.37 hours, that correspond to degrees of asynchronism from ≈ 1.76% to ≈ 5.96%.

  • Subjects / Keywords
  • Graduation date
    2019-06
  • Type of Item
    Thesis
  • Degree
    Master of Science
  • DOI
    https://doi.org/10.7939/r3-tt6h-yp36
  • License
    Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.