Meanwhile the important elements of what you ask are this...
1. A ship IS precipitated out of jump when it crosses the 100D line from any object (which is greater than that of the ship).
" Restrictions. Jump cannot take place within 100 diameters of body (star, gas giant, world, planetoid, or even another ship) larger than itself.
If a plotted course intersects a 100 diameter sphere around any object larger than the ship, the ship is "precipitated out" of jump space.
In System Jumps. It is possible to jump within a star system: The jump still takes a week (168 hours or so). In some cases, the jump is more efficient than using maneuver drive."
2. SO, if you plot a jump in a straight line from here to there, and between here and there there happens to be an object of sufficient size, then you aren't going to go all the way. You'll precipitate out of jump when you hit the 100D limit.
3. It is based on D rather than mass. Take that as an article of faith. We are talking about an object with some appreciable densitry however, so most gas clouds don't apply. If essence, the object must be a star or a world or a solid object ratehr than a nebula or comet tail.
4. Sometimes there is an uncharted or unexpected thing in the way (big ship, planetoid, whatever. That would make you precipitate out. BTW, this implies that there is a one-to-one mapping between jump space and real space.