It associates a star and a Jewish king, and may have been the prophecy that influenced the magi. At any rate, they probably made the association of a star with a Jewish king from what Jewish exiles told them of Old Testament prophecies. They were religious leaders, not kings. Later they were given names of Caspar, Balthasar and Melchior. D. There could have been more than three.
Gold is a gift for a king, frankincense is a gift for a priest, and myrrh is a gift for a funeral.
It took them some time to arrive. The magi did not arrive at the same time as the shepherds, and the shepherds are not said to have seen a star. The oldest theory is along these lines. There are no records of a supernova in this period. Comets in general were considered signs of bad events.