One week (168 hours - or 160 from the Companion) plus or minus. The time for a jump is independent of the distance travelled - half an AU or 6 parsecs. You pop into the jump-space universe, hang out for a week, and pop out. The 100D limit is pretty clearly articulated for precipitating out of jump, but you can jump at less than 100D with increasing risks of misjump. And as currently written the mechanic for entering jump is a little strained - it's a task chain, without indication that a 'failed' Astrogation check carries forward, since a failure 'must' be attempted again - so it never passes a negative DM to the Engineering roll. Therefore the misjump is always the engineer's fault... Would have worked better with the MegaTraveller uncertain task mechanics.
Core book, any jump within 100D is a DM-4. Companion makes it DM-8 within 10D and nothing in the rulebook(s) says you can't also take that DM-8 (or Core's DM-4) jumping from the ground. A referee might disagree.
But I do like the Companion's 'bad jump' rules, though they can get rather involved, especially on a ship with a lot of crew and passengers.
Yeah, that is what precipitated the question. We know that during jump you can be pulled out of jump prematurely if your path intersects a large gravity well. The 100D limit is the DEPARTURE limitation. What I was talking about was being beyond the 100D limit to ENTER jump.
We know that there is a time period to jumping, and it's the same for a jump of 1 or 6 parsecs. However, the books have always stated that being pulled out prematurely by a large gravity well also happens regardless of your original planned jump distance. So it is possible to plan a 24 parsec distance jump but only travel 3 and leave jump space because a star, gas giant or planet happened to be along the path of your planned jump (obviously your navigator needs to check their charts!)
From the mechanics explanation of jump we know that distance isn't a factor. Though we also know leaving jump prematurely is also not a distance factor. The explanation for jump, as written, seems to have a logical flaw in that it's trying to explain two diametrically opposed issues with the same explanation. MGT changes the equation further by restating the process and creating a jump bubble that degrades over time, and that is what sets your time period in jump. It, too, retains the gravity well thing that can pull you out of jump space.
Under the current rules you could be at 101 diameters and jump towards the planet, be in jump 1 week, and then emerge at the 100D limit 1 week later, having moved only 10,000km. That just seems very odd to me. What I think is that nobody tried to connect the dots and they just went with it without bothering to actually fix the explanation so that it remained constant. It's N-dimensional space and sure, the laws of physics may be different, that's a given. But when you inject 3-D physics into it that can also affect the N-dimensional, then it falls apart.