In Passages in the Void[1], these planets are the only places the machines were willing to reincarnate humanity after deciding that stars were too dangerous, having suffered the anguish of their humans being extinguished by our own Sun.

[1] A series of short stories by a Roger Williams, tagged localroger on kuro5hin, wrote back in the day. I gathered the parts together into an ePub suitable for iBooks. I'm checking with the author now to see if I can make it available. You can always read it on the kuro5hin site, linked from http://localroger.com/ (The Metamorphosis of Prime Intellect is something else entirely.)