2004MNRAS.350...95P

High-resolution spectroscopic observations have been made of a number of southern Cepheids. The stars studied were part of a long-term programme to observe southern variable stars and to complete a data base of radial velocities over a long time interval. The radial velocities have a precision of ∼300 m/s, allowing the detection of velocity differences of ∼1 km/s with confidence. Our new data provide a consistent set of data against which other sources of data can be compared.

Masses were determined for two systems, the 9-d Cepheid S Mus (6.2±0.2 M_☉) and the 5-d Cepheid V350 Sgr (6.0±0.9 M_☉). For another seven Cepheids (Y Car, YZ Car, AX Cir, BP Cir, V636 Sco, W Sgr and T Mon), new or improved orbital solutions were found.

New results presented here include the first orbital solution for AX Cir, a completely revised orbital solution for YZ Car, which established its eccentricity and orbital motion, and a new pulsation period (2.398 19 d) for BP Cir. The pulsational mass determinations provide further confirmation of the convergence of mass determinations between dynamical and evolutionary methods.