  The splitting number of a plane irreducible curve for a Galois cover is
effective to distinguish the embedded topologies of plane curves. In this
paper, we define a connected number of any plane curve for a Galois cover whose
branch divisor has no common components with the plane curve, which is similar
to the splitting number. We classify the embedded topology of Artal
arrangements of degree $b\geq 4$ by the connected number, where an Artal
arrangement of degree $b$ is a plane curve consisting of one smooth curve of
dgree $b$ and three total inflectional tangents.
