In the mid-24th century, on stardate 40001.1, Lieutenant Darien Wallace was born on Altair IV. This lieutenant's personnel file appeared in a hallucination of Deanna Troi's. (TNG: "Eye of the Beholder", okudagram)
In 2371, a resident of this world, one Doctor Henri Roget of the Central Hospital of Altair IV, was awarded the prestigious Carrington Award for his work in the field of medicine. (DS9: "Prophet Motive")
Altair IV was also the name of the alien world featured in the film Forbidden Planet.
According to the Star Trek: Star Charts (page 44) and on the chart "United Federation of Planets I", the Altair system was located in the Alpha Quadrant. This system, also known as Alpha Aquilae, was a single star system. Primary was a Class A star with a magnitude of +3, which was ten times brighter than Sol. Altair IV was listed as a member planet of the Federation in 2378.