hierarchical multiple system
râžmân-e bastâyi-ye pâygâni
Fr.: système multiple hiérarchique
A → multiple star system in which the stars can be divided into two groups, each of which traverses a larger orbit around the system's center of mass. Each of these smaller groups must also be hierarchical, which means that they must be divided into smaller subgroups which themselves are hierarchical, and so on. Hierarchical multiple systems have long-term dynamical stability.
non-hierarchical multiple system
râžmân-e bastâyi-ye nâpâygâni
Fr.: système multiple non hiérarchique