^ Yes, random. You have a 1/400 chance at popping out at any particular spot. I do not know for sure whether in a system with celestial objects (planets stars, etc.) if you have any chance of popping out on top of a planet or sun (notwithstanding passing the roll mentioned below).
The chance of hitting a celestial object in a system when aborting hyper is not the same random calcluation (ie Chance is not in fact = NumCObjects / 400):
Piloting Skill = The appropriate piloting skill level that corresponds to the ship type that is being flown.
NumPlanets = Number of planets, suns, asteroids, moons, and comets in the system that you emerge at. (I think this also includes black holes)
Rand = Random number between 0 and (300 + 20 * Piloting Skill).
Ship Destroyed = True if 4 * (NumPlanets) > rand.