"Take over your enemy`s planet. The planet must be of "special" type and your fleet must have a Colony Ship, Luker or Sower."

When planet is special type? Is that means i cant takeover every enemys planet? Can i takeover someones capital planet?

Special ("instance") planets are located at coordinates X:1:1. If I'm not mistaken, they cannot be made capitals.

So i cant takeover planet of my neighbour?