Barycentre

A barycentre is a mutual centre of mass around which two or more bodies orbit.

The barycentre between stars in the Shinrarta Dezhra system appears as both the lines and an X, due to the planets that orbit the barycentre.

They can be seen on the System Map as lines forming three sides of a rectangle, linking the bodies indirectly. If anything else is orbiting those bodies collectively (as opposed to individually), the barycentre is additionally marked with an X.