Hi! It means it's orbiting the primary star (and not anything more convenient that can be pointed out) and is somewhere beyond 10k units away from it. (2k units = 1 map grid cell)
*proceeds to choke on wine* That explains my need to use the neutrino detector.
Anything that's "outer reaches" isn't worth it. If it's a research station I'll give serious consideration but usually will still pass. I don't really use the neutrino detector due to the high cost of keeping volatiles on hand to run it. They deplete FAST. If you've got cargo space and money to burn then go for it; I'm just not dedicated enough to exploring to feel like doing it.
I actually just accept it anyway and salvage them once I find it so that the mission won't pick that particular object again. It becomes more manageable when I pick off undesirable mission farm points.