Abstract

Six percent of the FK5 stars of fundamental proper motion pass the convergent point test for membership in the IC 2391 supercluster if stars within 30° of the convergent and anticonvergent points (sin λ<0.5) and values of V_TOT < 25 km/s are dismissed and a tolerance of 0.1 V_TOT (0.1/sin λ) is placed on τ/ν. One third of these stars are eliminated by the luminosity test, using calibrations of available photometry, and an additional 40% are removed by the imposition of the requirement that ρ(Clus)-ρ(Obs)<3 km/s. This leaves 1% of the FK5 stars as supercluster members, which show a spread of about 10⁷ yr, if 5 × 10⁷ is the upper age limit of the early-type stars or 10⁸ yr, if 5 × 10⁷ is the minimum age. An age spread is also reflected in the lower main sequence stars. Interesting supercluster members include the spectroscopic triple HD 21364 (RR 1038), the ellipsoidal variable HD 1061 (UU Psc), the light variable HD 27290 (RR 1338) which lies in the Böhm-Vitense decrement (BVD), the red variable HD 89388 (RR 4050=V337 Car), and the peculiar A type, iron and barium underabundant and calcium, silicon, and helium overabundant, star HD 143459 (RR 5959). The FK5 stars were also tested with the contrived convergent points of δ=±90° but only the expected random selection of stars was found.