SR2 Rebooted question - what is 'unidentified: x'
 

I've started playing SR2 rebooted. I'm about 2 years into the game and I'm starting to see numbers unders some star systems. When I click on the star map for said system I see, 'Unidentifed: 7' or some other number listed underneath the planet info.

What is this?

<edit>
Ok, I think I answered my own question. I picked up the artifact Prolonger which appears to be able to identify the number of ships in nearby star systems. I guess this could be useful when deciding to drop in on a Dominator battle.

thanks,
C4