GURPS Space - assistance

[Whill]

Thank you. Welcome to the "Primordial System"...

I envision a binary system, but the twist is that a G2 V star ("Astra") more luminous than our sun but the same mass, is a companion to a black hole ("Thanatos"), with the planetary system around the companion. I want them to be the maximum distance apart possible for the dice roll, which I calculated to be 600 AUs (12x50).

I don't want the star to just orbit around the black hole - I instead want them both to technically orbit around a gravitation barycenter that is of course closer to Thanatos due to minimum black hole mass being higher than Astra's. I think I consulted an outside equation for this step but I worked out a barycenter to be 10 AUs from Thanatos, which has a mass of 59 solar masses (likely to be a conglomeration of multiple black holes).

Anyway, in calculating the forbidden planetary orbit range, I got an Inner Edge of 200 AUs and an Outer Edge of 1800 AUs! My first question is what the Outer Edge actually means here? According to this system, does that mean that no planets could form around Astra because it is between 200 and 1800 AUs away from Thanatos? Or does that just mean no planets could orbit Thanatos in that range, but the companion star's own planetary orbit stability would be uneffected? Of course Thantos doesn't need planets, just Astra.