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Paper: On the System Parameters of the Dwarf Nova EM Cygni
Volume: 362, The Seventh Pacific Rim Conference on Stellar Astrophysics
Page: 241
Authors: Welsh, W.F.; Froning, C.S.; Marsh, T.R.; Reimer, T.W.; Robinson, E.L.; Wood, J.H.
Abstract: EM Cyg is a bright, eclipsing, double-lined spectroscopic binary and therefore potentially a very important cataclysmic variable because in principle a full set of accurate system parameters can be determined for it. However, measuring the system parameters has turned out to be difficult due to the contaminating effects of a third star along the line of sight. In this work we use FUSE spectroscopy to infer the orbital motion of the white dwarf star. We use the cross correlation method to measure the radial velocities and pay particular attention to subtle systematic effects that can bias the derived orbital velocity. With our new value of orbital velocity we re-derive the binary system parameters using a Monte Carlo method that handles non-Gaussian constraints. The resulting system parameters are more reliable than previous estimates and will facilitate future work on EM Cyg and its accretion disk.
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