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Paper: Three-dimensional SPH simulations of stream-disc overflow in cataclysmic variables
Volume: 261, The Physics of Cataclysmic Variables and Related Objects
Page: 551
Authors: Speith, R.; Kunze, S.
Abstract: The interaction of the infalling gas stream with the rim of the accretion disc in cataclysmic variables has been studied numerically. These studies span a wide range of orbital periods, mass ratios, mass transfer rates, disc sizes, and thermal states of the discs. A common feature in all simulations was the occurrence of stream overflow. We have found that the accretion stream is not stopped at the impact region (the bright spot at the outer rim of the disc), but a substantial part of the matter is deflected vertically and flows in a more or less diffuse stream to inner regions of the disc, hitting the disc surface close to the circularisation radius at orbital phase ~0.5. The overflow can cause the X-ray absorption dips observed in many CVs and LMXBs around orbital phase 0.7. Under certain circumstances, parts of the overflowing stream bounce off the disc surface again and may cause an additional absorption region around orbital phase 0.2. In our simulations most of the infalling matter reaches the inner disc very quickly. This might have an influence on the long-term evolution of the disc and therefore should be taken into account in corresponding calculations.
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