Period variations commonly appear in close binary systems, due to the possible mass transfer between their component stars, angular momentum loss from the binary systems, or perturbation by a third body (light travel time effect).
V752 Cen is a triple-lined spectroscopic quadruple system, and the tertiary and fourth components may make up a faraway binary system. The period variation of V752 Cen over the nearly half century is really unusual, and is potentially related to effects from the possible presence of a nearby third star or of a pair of stars in a second binary. Hierarchical close binary systems are probably common and the far away components may remove angular momentum from central binaries and result in tidal tightening of inner binaries.
However, no observational evidence on dynamic interactions between inner binaries and additional companions was reported. In that respect, V752 Cen is a very interesting hierarchical close binary system with significant research value. The research on its light curves and period variations suggested that dynamic interactions may have happened between the inner binary and companion stars orbiting it.
Period variations of close binary V752 Centaurus (Image by ZHOU Xiao)
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