P3X-403
Astrographical information
Galaxy	Milky Way
Societal information
Race	Unas, Tau'ri
Technological period	Primitive
Earth interest	Naquadah mining
Under control of	Unas
Out of universe information
Appearances	"Enemy Mine"

[Source]

P3X-403 was an Unas populated planet in the Milky Way galaxy, which held a Stargate and had huge resources of Naquadah. The Goa'uld brought the Unas there to mine the naquadah, but the Unas rebelled against them and the mines thus became a sacred place to the Unas. Stargate Command garnered a treaty with the Unas which included that the Unas would receive food and supplies if they extracted the naquadah for the Tau'ri. Considering the presence of Serpent Guard helmets on a memorial showing the instruments of Goa'uld torture, the planet may have originally belonged to Apophis. (SG1: "Enemy Mine")