An n-sun is the graph with 2n vertices consisting of an n-cycle with n pendent edges which form a 1-factor. In this paper we show that the necessary and sufficient conditions for the decomposition of complete tripartite graphs with at least two partite sets having the same size into 3-suns and give another construction to get a 3-sun system of order n, for n ≡ 0, 1, 4, 9 (mod 12). In the construction we metamorphose a Steiner triple system into a 3-sun system. We then embed a cyclic Steiner triple system of order n into a 3-sun system of order 2n − 1, for n ≡ 1 (mod 6).

No abstract