Moving Pairs among the A-Type Stars within 20 PC

Abstract

view Abstract Citations (1) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Moving Pairs among the A-Type Stars within 20 PC Vandervoort, Peter O. Abstract Among the 20 A-type stars within a distance of 20 pc from the sun there are four pairs and one triple system in which the components have space velocities which differ by 4 km/sec or less. In a fifth pair the space velocities of the components differ by 5 km/sec. Thus 13 of these stars, two- thirds of the sample, appear to be components of moving pairs or the triple system. Typically, the components of these systems are separated by distances of the order of a few parsecs. If these stars could be considered to be a random sample of a kinematically homogeneous population of stars governed by a Schwarzschild distribution of the velocities, then the probability of the occurrence of so many close pairs (in velocity space) is very low. Therefore, it is possible that one is dealing here with physical pairs. The arrangement of the components of these systems in the color-magnitude diagram may be consistant with this possibility Such pairs could be used to derive a lower limit on the time of relaxation for the motions of stars in the solar neighborhood. The suggested pairs are: Sirius and ~ UMa, a Pic and ~ Leo, p Pic and ~ Cap, ~ Ara and a Cep, and 6 Leo and a Oph. The first of these is associated with the Ursa Major Stream. The components of the triple system are a Gem, K Phe, and a PsA. Additional interest attaches to this system because a Gem is itself a multiple system containing an additional A-type star. This work has been supported in part by the Office of Xaval Research. Publication: The Astronomical Journal Pub Date: September 1967 DOI: 10.1086/110562 Bibcode: 1967AJ.....72S.833V full text sources ADS | data products SIMBAD (13)