Amphion was a previously dead star in the antimatter universe that was the counterpart to the star Beta Niobe in the prime universe.
In 2270, Karla Five, from Arret, was investigating the dead star. She got caught unaware as Amphion went supernova and came to life and pulled her ship into the star. Instead of burning up, she passed through the Beta Niobe nova, into the prime universe where everything operated in reverse to her universe. She hypothesized that two stars going nova at the same time in both universes created a gateway, through which ships could pass through. (TAS: "The Counter-Clock Incident")