Yes, surprisingly stable. Quoth wikipedia: "The orbits of planets b-g are nearly in resonance, having relative periods of approximately 24/24, 24/15, 24/9, 24/6, 24/4 and 24/3." They're all supposedly Earth-sized, meaning .76-1.13 R?, or "more Earth-sized than Mars is." The downside of all this stability and closeness to the star is that they're very likely tidally locked. Which should help your hack SF writers even more by making single biome planets!
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