Dynamics of quadruple system Finsen 332 = ADS 11640 = HIP 92027 = WDS 18455+0530

Abstract

In 1829 Struve discovered a double star denoted as STF 2375 AB later on. Its separation was 2". 2. It was noticed by Finsen from the Southern Observatory (Johannesburg) in 1953 that the components A and B are close binaries with separations about 0".15. The motion within this quadruple system - FIN 332 Aa and FIN 332 Bb - has been monitored from that time on. The data about the motion of these close binaries are analyzed by the present authors and the preliminary orbital elements are calculated for each of them. The dynamical parallax from the obtained period and the semi major axis for pair FIN 332 Bb agrees completely with that obtained from the Hipparcos program. In the case of FIN 332 Aa a somewhat higher parallax but within the error limits following from the errors of the period and semimajor axis, is obtained and it agrees with the parallax for FIN 332 Bb. The dynamical masses for the components of both systems are as expected for their spectral type A1V (all of them belong to the Main Sequence and here one uses Angelov’s (1993) relation). According to our results, the motion of both systems takes place approximately in the same plane, confirming thus some general properties already noticed in the case of multiple stars.

Keywords

• binaries: close