Nucleations Extent?

[foodchain]

Does nucleation lead to any product larger then monoatomic in state? Such as nucleation is required for planetary formation even? Stars if I am correct have to have a certain mass to go nuclear right? So if a star is roughly homogenous would it be something in the order of buckyball on steroids or astronomical units of measurement, Or at certain masses would other natural phenomena start to take over such as atmospheric patterns due to the motion of say energy and matter within the system?

 

I am just wondering if nucleation is sort of a seed state that can lead to a certain types of phenomena from molecular in scale to how large or what is the cut off on the effect of nucleation.