Ceres Alpha

 was a planet discovered by WorldCorp which was perfect for human colonisation — the atmosphere closest to Earth's of any planet known to WorldCorp. The only problem was that it had been previously inhabited. WorldCorp, under the guidance of its employee Gaskill Tyran, undertook a programme to actively conceal the existence of Ceres Alpha's former inhabitants, lest they ruin their profit margin. (PROSE: Dark Progeny)

The Eighth Doctor told Scarlette that he had recently had an adventure in "Ceresalpha, where the children were as ghosts". (PROSE: The Adventuress of Henrietta Street)