Wikia

Alpha Omicron VII was the seventh planet in the Alpha Omicron system. In 2367, it was while orbiting this planet that the USS Enterprise-D discovered the lifeform dubbed "Junior". (TNG: "Galaxy's Child")

According to the script of the episode, Alpha Omicron VII was identified as a gas giant.

On the StarTrek.com website, this planet was described as a "Jupiter-like gas giant." [1]

Alpha Omicron VII