Herschel graph,  a bipartite undirected graph, is named after Alexander Stewart Herschel and has eleven vertices and 18 edges among its other qualities.
In graph theory, a branch of mathematics, the Herschel graph is a bipartite undirected graph with 11 vertices and 18 edges, the smallest non-Hamiltonian polyhedral graph. It is named after British astronomer Alexander Stewart Herschel. 
