If hacked planets don't count against scan success, then how do I know if the planets I'm purging aren't the ones I've hacked?

Is there any way a planet could have a tag somewhere saying how the planet was obtained? It would probably take up space if it were a whole tab and it might be difficult to put on the planet screen if the view is universal. The data is kept somewhere already though. I'm guessing a hacked planet has the same properties for scanning as one that is shared, then settled.

If I purge planets I've hacked then I'm doing myself a disservice the next time I scan and I'm also getting rid of any "padding" the free, crappy planets provide when I critically fail a hack.

very good question

does the planet provided by alien star charts count against scan chance?

All planets discovered from all sources count towards your scan chance, with the exception of shared planets. Those are not permanent and do not count towards your chance.

As for a planet indicator, a planet "history" might be an option - someone mentioned something like that as a suggestion before. It could work like a ship's log, and show recent actions.

i think the should be somewere were you can see all the output for your planets

While there isnt one place where this is shown between the research page and the trade page that info is shown