Cross-correlation radial velocity measurements of chromospherically active binaries

A.G. Gunn, J.C. Hall, G.W. Lockwood, J G Doyle

We present observational radial velocity curves for 12 chromospherically active binary systems and individual measurements for a further 5 systems. These binaries are LX Per, V471 Tau, El Eri, OU Gem, GK Hya, TY Pyx, Z Her, MM Her, V772 Her, ER Vul, BD-004234, MY Cyg, AR Lac, KZ And, RT And, SZ Psc and EZ Peg. Six of our target binaries do not agree with published ephemerides or orbital parameters. We also present a rigourous derivation of the resolution limit for binary star cross-correlation radial velocities. Using synthetic spectral data we investigate the errors induced by rotational broadening, signal-to noise ratio, spectral-type mismatch and luminosity ratio. Key Words: stars:binaries:close-stars:binaries:spectroscopic-techniques: radical velocities.