Absolute dimensions of eclipsing binaries. II. The early-type semidetached system V Puppis.

A complete spectroscopic and photometric reanalysis is undertaken for V Pup in order to improve observational data to the point where a detailed theoretical calculation of its evolution will yield significant new results. The new spectroscopic orbital elements yield smaller masses than the previous data, and although the system is close to contact, the semidetached nature of V Pup can be unambiguously established. Critical reexamination fails to confirm any of the previous observational evidence for circumstellar matter, and alternative explanations of the observed anomalies are proposed. It is suggested that V Pup began its evolution as a near-contact system whose mass ratio is close to unity, so that Case A mass exchange set in before the original primary star had evolved, and that the rapid mass transfer was stopped before the mass ratio reversal had gone to extreme values.