A 3D model for \(\alpha\) Gem AB: orbits and dynamics
The well-known multiple star system, Castor, and particularly, the [(Aa, Ab), (Ba, Bb)] subsystem, was studied in detail. After a rigorous analysis of the quality controls, a new solution for the visual orbit yielded new values for the different physical and orbital parameters of the system. In addition, a comprehensive investigation of the orbital configuration of the quadruple system allowed us to provide both accurate individual masses and orbital inclinations of the spectroscopic subcomponents, as well as a new value of its orbital parallax. Finally, by means of a numerical analysis of the long-term dynamics, we obtained the most probable values of the nodal angles of the two spectroscopic subsystems for the first time.
Furthermore, the full characterization of this remarkable system allowed us to discuss some interesting features of its present configuration. In this way, we concluded that the eccentric (Aa, Ab) subsystem is yet undergoing Kozai-Lidov cycles whereas, on the contrary, the circular (Ba, Bb) subsystem has probably already reached a stable stage.
KeywordsAstrometry Celestial mechanics Binaries: spectroscopic Binaries: visual Stars: fundamental parameters Stars: \(\alpha\) Gem AB (Castor)
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