To further clarify what triggered this thought.
Over thousands of years of inter system travel and conflicts it seems that laying in a siege to interdict a system that already has a bustling commerce (hence needing regular fuel supplies) would have some established tactics if it was a viable strategy.
Jump in, unleash a volley of attacks and leave makes good sense.
Stationing large numbers of resources in a system to prevent any interactions/resupply for weeks/months/years seems to not really be effective if even possible.
That is why the question.
Hmm, having wargamed extensively in the Third Imperium setting, including playing all the Trav-associated boardgames at one time or another, I see sieges occurring most frequently when a world/system cannot be conquered quickly (think the difference between what Russia wanted to happen in its 2022 invasion of rump Ukraine, and what we've actually had happen after the 'three day war' plan failed).
So, for example, in GDW's 5FW game you might jump into a system as a Zhodani fleet and hope to bounce the defenders quickly. Those defenders are usually SDB squadrons/flights and planetary-based defenders. There might also be an Imperial fleet or naval elements hanging around of course as well.
If things go well, it is possible to (in a one-week game turn) engage in a space battle against any Imperial fleet, dispatch it, engage in a space battle against any SDBs and defeat them, bombard the main world and land troops to round up any defenders. You leave a garrison, refuel, recall the troops you're taking with you to ships and jump on to your next objective.
But things don't always go so smoothly. You might lose the naval battle. The SDBs might not hang about to be defeated and instead scatter into "hides" across the system from which you know they may later emerge to wreak havoc. The planetary-based defenders might ride out your bombardment and/or defeat your initial landing.
At that point the siege begins, if (and only if) you decide to hang about and try to reduce the defenders because that world is of strategic significance (in the games because it is worth Victory Points or VPs to you or to the enemy or to both of you). Alternatively, you might have to hang about for the simple reason that your fleet (or important elements of it) can't refuel unless you secure the gas giant (if you're partially streamlined) or secure the planet/starport/naval base if you can't refuel elsewhere. The defender will be making it difficult to get that refuelling done, leaving you in place with all effort needed to secure those refuel points.
Anyway, just a few thoughts. YMMV!