Maybe they were frontier systems at the time or something, but then the systems in the lower left (such as Dubhe and Alphard) should also be red, so I don't know really...
Oh BTW it seems that they made a few changes from FS1 to FS2:
The Mirfak system in the upper right corner was renamed to Mirfax. (although it may have originally been this way)
Procyon A was renamed to Procyon.
And of course, the unlabeled systems were changed to Epsilon Pegasi and Gamma Draconis.

Also, regarding the Luyten system, I actually found that star on a table in an astrophysics textbook, and it is apparently Luyten 726-8A rather than 726-BA.
[This message has been edited by CP5670 (edited 01-28-2002).]