 This is quite distinct from the far more common observations of alternating period increases and decreases explained by the Applegate mechanism.Monotonic period increases have been attributed to mass transfer, usually (but not always) from the less massive to the more massive star

The components of binary stars are denoted by the suffixes "A" and "B" appended to the system's designation, "A" denoting the primary and "B" the secondary.The suffix "AB" may be used to denote the pair (for example, the binary star α Centauri AB consists of the stars α Centauri A and α Centauri B.)