SPH Simulations of Negative (Nodal) Superhumps: A Parametric Study

Jun, 2009
14 pages
Published in:
  • Mon.Not.Roy.Astron.Soc. 398 (2009) 2110
e-Print:

Citations per year

2009201320172021202501234
Abstract: (arXiv)
Negative superhumps in cataclysmic variable systems result when the accretion disc is tilted with respect to the orbital plane. The line of nodes of the tilted disc precesses slowly in the retrograde direction, resulting in a photometric signal with a period slightly less than the orbital period. We use the method of smoothed particle hydrodynamics to simulate a series of models of differing mass ratio and effective viscosity to determine the retrograde precession period and superhump period deficit ε\varepsilon_- as a function of system mass ratio qq. We tabulate our results and present fits to both ε\varepsilon_- and ε+\varepsilon_+ versus qq, as well as compare the numerical results with those compiled from the literature of negative superhump observations. One surprising is that while we find negative superhumps most clearly in simulations with an accretion stream present, we also find evidence for negative superhumps in simulations in which we shut off the mass transfer stream completely, indicating that the origin of the photometric signal is more complicated than previously believed.