What are you talking about....
You dont need a star for planets to retain existance.
The star is usually required for a planet to be made, yes, but its not required for a planet to stay in existance.
A planet without a sun will simply stay in place, these planets are usually dead planets or poison ridden crap holes (as I like to put it)
As for our system, Pluto would eventually fling off into space over a matter of generations, continueing to gain speed until it slamme dinto something or exploded into an asteroid.
A planet rotating around a star will eventually be destroyed if the stay explodes, unless the star simply "dies" and turns into a black dwarf (dead rock) and will then retain no gravitational force, and thus the planets will lightly be let off their axis, and slowing obtain their own "rotation" in that system, but that really depends, the small the planets will most likely slowly fling off into outerspace, while the bigger ones gravity will pull on eachother and create a magnetic effect, and they will all rotate around eachother or in a sister lock, which would stop them from flinging into space.
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