Hyperbolic components and cubic polynomials

In the space of cubic polynomials, Milnor defined a notable curve $\mathcal S_p$, consisting of cubic polynomials with a periodic critical point, whose period is exactly $p$. In this paper, we show that for any integer $p\geq 1$, any bounded hyperbolic component on $\mathcal{S}_p$ is a Jordan disk.