The UP like the UA points to Merope(unless in Merope system).
The UA spawn in a shell around Merope. When the UA first appeared, it did not spawn in a shell and it did not point to Merope.
As there seem to be a link between pointing and shell forming, it's not unlikely that the UP does the same.
Some shell scenarios:
- UP spawns in UA shell. Possible but if that is the case, it's quite rare. Lots of commanders have searched in the shell.
- UP spawns in a bigger shell. Possible but if that shell is between 200-500ly it would pass directly trough the bubble. Not likely that this would pass unnoticed.
- UP spawns in a smaller shell. Possible and not as well investigated as the current shell, but quite a lot of searching has been done.
- UP spawns inside Merope system in a shell around M5C. Massive searching done in the Merope system. Not very likely.
- UP spawns under certain conditions e.g. close to planets in the UA shell. Quite a lot of searching performed without result, but still a possibility.
- UP spawns in a specific sector of the UA shell, e. g. towards California nebula, Witch Head or Polaris. To my knowledge we haven't done this a lot yet.