[SPACE 4e] System Design help? (star systems that is...)

[Jon F. Zeigler]

I'd go with a wide binary star system, in which both stars are about the same mass and age, and are reasonably Sol-like. It's unlikely but feasible to get two worlds in the habitable zone of a single star. Three is really stretching it, but the third one can orbit the companion star.

This is, oddly enough, exactly the arrangement of the Manticore system from David Weber's "Honor Harrington" novels. If I remember correctly, Manticore (the planet) and Sphinx orbit the star Manticore-A, while Gryphon orbits Manticore-B. Manticore is pleasantly Earthlike, Sphinx is further out and has very severe winters, and Gryphon has high axial tilt yielding very strong seasonal variations. Weber may have borrowed a little too enthusiastically from Napoleonic history, but his worldbuilding is fairly plausible.