North Polar Basin (Mars) suggest that a body approximately 0.02 Mars masses in size is capable of producing a sizable debris disk in Martian orbit, on the order of 5x10 kg, with a significant fraction of the material remaining close to Mars. This figure lies within the estimated mass range necessary to form the two moons, as other data suggests that only 1% of the mass of an accretion disk successfully forms moons. There are several other large impact basins on Mars that could have ejected enough debris to form the moons. Analysis of Mars Global Surveyor data found mineral deposits similar to terminal
Shepherd Moons and elements of Celtic and New age music, though Enya believes her music does not belong in the latter genre. "Shepherd Moons" received generally positive reviews from critics and became a greater commercial success than "Watermark". It went to number one on the UK Albums Chart and peaked at number seventeen on the "Billboard" 200 in the United States. The album was certified multi-platinum by the British Phonographic Industry and Recording Industry Association of America for shipments of 1.2 million and five million copies, respectively. Between 1991 and 1994, Enya released four singles from "Shepherd Moons": "Caribbean Blue", "How Can