is a binary star
system composed of A
components, both of which are red dwarf
stars. These stars orbit each other every 44.6 years. The fainter companion B is a flare star
and has been given the variable star
designation "DO Cephei". It is an irregular flare that typically doubles in brightness and then returns to normal over an 8 minute period.
On average, the two stars are separated by 9.5 AUs, which is roughly the average distance of Saturn from the Sun. However, their eccentric mutual orbit causes their distance to vary between 5.5 AUs at periastron, to 13.5 at apastron.
James Kaler, Extreme Stars
: Cambridge UP, 2001), p. 32.