I think "mere" kind of makes sense at these scales?
I mean the nearest known star (Proxima Centauri) is 40,208,000,000,000 km away. (Guess it depends on whether you're using "American" Billions or not...)
Given that you're talking about an object in our solar system, I think almost all astronomers would not use "mere" or parsecs.
Ah, missed the "in our solar system" bit :).
What are "American" Billions? I'm an American and AFAIK our 'billions' is the same as anyone else's.