61 Ursae Majoris is a star system (also known as the Archer system) centered around yellow dwarf star (spectral class G8V) of the same name located about 9.5 parsecs (31 light years) from Earth, where it is visible in the constellation of Ursa Major. The system was named for Captain Jonathan Archer, who surveyed the system in 2151 aboard the Earth Starfleet starship Enterprise.
In 2366, the USS Enterprise-D traveled to the Archer system following their investigation of a suspected temporal anomaly. In an alternate timeline, the fourth planet of the Archer system was the site of a battle between the Enterprise-D and Klingon warships. (TNG episode: "Yesterday's Enterprise")
In another alternate timeline, the Archer system was occupied by Dominion forces in 2373, who hoped to synthesize Ketracel-white from a lichen native to one of the moons in the system. (TNG short story: "Gods, Fate, and Fractals")
- Since 61 Ursae Majoris is a "real" star, modern scientists know a few things about its makeup that weren't in its Star Trek mentions.