I assume you're not including Pluto-Charon here (presumably since Pluto is now demoted to "dwarf planet")? Their mass ratio is only about 8:1, which is far smal

I assume you're not including Pluto-Charon here (presumably since Pluto is now demoted to "dwarf planet")? Their mass ratio is only about 8:1, which is far smaller than Earth-Moon, 81:1.