If memory serves, the map just subtly highlighted stars where there was something more than mere resources to be found. It could be backstory, useful items, dan

If memory serves, the map just subtly highlighted stars where there was something more than mere resources to be found. It could be backstory, useful items, dangerous enemies, etc. The marking was so subtle that I didn't even notice it until my second playthrough, when I was deliberately trying to discover more stuff.