Harry (Alan Tudyk) gazes at his home world's sun "still forty-six light-years away", a bright star below the Big Dipper where no bright star is known - a bit of visual license by the creators (or perhaps Harry's sun is especially prominent to alien eyes). Though its position in the sky is slightly off, Harry might be talking about 47 Ursae Majoris (Chalawan), a yellow dwarf star forty-six light-years away and known by astronomers to have at least three planets.
Harry (Alan Tudyk) states his home world is 46 light years away. A light year is the distance light will travel in one year. This is an especially useful unit in measuring the vast distances of space. Light travels at about 186,000 miles per second. This adds up to being 5.88 trillion miles in a year. Therefore, Harry's planet is about 270.48 trillion miles from Earth.