Forbidden induced subgraphs for star-free graphs

Let H be a family of connected graphs. A graph G is said to be H-free if G is H-free for every graph H in H. In [1] it was pointed that there is a family of connected graphs H not containing any induced subgraph of the claw having the property that the set of H-free connected graphs containing a claw is finite, provided also that those graphs have minimum degree at least two and maximum degree at least three. In the same work, it was also asked whether there are other families with the same property. In this paper we answer this question by solving a wider problem. We consider not only the claw-free graphs but the more general class of star-free graphs. Concretely, given t ≥ 3, we characterize all the graph families H such that every large enough H-free connected graph is K1,t-free. Additionally, for the case t = 3 we show the families that one gets when adding the condition |H| ≤ k for each positive integer k.