what about the aura
and as far as i know, yes more trade ports give you more income.
Refineries max out at 3, theres a great thread about how refineries work, but put simply they boost the income of the extractors in the same, and adjacent gravity wells.
Advent trade ports have a 'Resource Focus' that only works in the same gravity well
this was the second last concept in the game i figured out, the last being Shield Mitigation D=