memory alpha

Gemma, also known as Alpha Coronae Borealis or 5 Coronae Borealis, was a star system in the Alpha Quadrant.

Components

Stellar system

This was a binary system. The primary Alphecca (the proper name for Alpha Coronae Borealis A) was an A-type dwarf. The companion Alpha Coronae Borealis B was a G-type dwarf.

Stellar cartography

The Gemma system was visible from Earth in the constellation Corona Borealis. It was approximately 75 light years from Sol.

In the 2150s, this system's position was labeled on an United Earth star chart which was displayed in several crew and guest quarters aboard the Enterprise. (Star Trek: Enterprise, set decoration)

In 3191, this system's location was labeled on a star chart. (DIS: "Red Directive")

In 3195, the position of Gemma (Alpha Coronae Borealis) was labeled on a Federation star chart which was used in Starfleet Academy's Temporal Mechanics classroom. (SA: "Beta Test") Systems affiliated with the Federation, including this one, had blue labels. (SA: "Beta Test")

Later that year, this system's position was labeled on a Federation star chart which was displayed on the bridge of the USS Athena. (SA: "Come, Let's Away")

In 3196, during the Omega-47 crisis, the location of Gemma (Alpha Coronae Borealis) was depicted on star charts and readouts used across several locations on the USS Athena to locate, monitor, and respond to the Omega-47 mines laid by the Venari Ral. This system was outside the barrier. (SA: "300th Night", "Rubincon")

This star system was only mentioned in writing.
Information on this system was derived from the episodes and films, the reference works Star Trek: Star Charts and Stellar Cartography: The Starfleet Reference Library, and real-world sources. The reference works were used extensively in the creation of star charts seen in Star Trek: Discovery, Star Trek: Picard, Star Trek: Strange New Worlds, Star Trek: Prodigy, Star Trek: Lower Decks, and Star Trek: Starfleet Academy. The real-world information added to the article was current as of 2026.
The star chart seen in the series Star Trek: Enterprise made its first appearance in Crewman Daniels quarters in "Cold Front". It was also seen in several other episodes of the series, from 2151 to 2154. (For more information, see Federation star charts#United Earth Alpha/Beta star chart)

External links