Phantas 61 was a planet in the Norvel system, the most remote world in that system. Phantas 61 was presumably home to a native humanoid race called Phantasians.
Phantas 61 was a successful mining world, and attracted a number of off-world settlers. In the early 24th century, a group of Red Nasats, rare emigres from their homeworld, settled on Phantas 61. by the 2370s, the population of also included Arcturans, Betelgeusians, and others.
In 2366, business entrepreneur Rod Portlyn purchased the planet, and hired a Phantasian citizen, Elless, as his right-hand man overseeing mining operations there. Over the following decade, Portlyn pressed the Phantasians to meet ever-increasing business goals in order to finance his growing empire, and quickly drained the world of its resources. At this point, Portlyn developed plans to convert Phantas 61 into an interplanetary waste dumping site. This led to the creation of the Taru Bolivar, dedicated to stopping Portlyn from further exploitation of other worlds.
In 2376, cryptographer Bartholomew Faulwell of the USS da Vinci discovered the link between a series of terroristic bombings and Phantas 61 in an encoded computer chip discovered on an injured bomber, Jaxxon. In those files, the planet's name was transliterated as "Fantasixun".
Once the Starfleet crew discovered Portlyn's unethical business practices in the Norvel system, Portlyn's agents launched an attempted genocidal on Phantas 61. Fortunately, a missile armed with a powerful biological weapon was diverted by da Vinci engineer P8 Blue.
Once these facts and events became known, Portlyn lost his ownership of Phantas 61, and much of the surrounding "Corporate Corridor" region, to rival business owner Patrice Bennett. Bennett then announced her intention to relocate an industrial research complex from nearby Vemlar to Phantas 61. (SCE eBook: The Art of the Deal)