homework and exercises - The mass and separation of binary system with only information about one star

If we can observe that a star and an unmeasurable planet are in circular orbit around a common center of mass. If we know the speed of the star to be $100\,m/s$, the mass of the star to be $2 \cdot 10^{33}\,g$ and a period of $432,000$ seconds. how can we try to calculate the separation, the mass of the second planet? Can make approximation when appropriate

I'm confused because I'm not sure if there's enough information to solve without making assumptions on the mass or the radius of the second planet. But that's what the question is asking

the only thing I can really calculate here is the orbit radius for the star with the velocity and the period.

Any help would be welcomed.