memory alpha

51 Pegasi was a star system in the Alpha Quadrant.

Components

Stellar system

This was a single star system. The primary Helvetios (the proper name for 51 Pegasi) was a G-type dwarf. (ENT: "Cold Front")

Stellar cartography

The 51 Pegasi system was visible from Earth in the constellation Pegasus. It was approximately 51 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 3195, this system's position was labeled on a Federation star chart which was displayed in Starfleet Academy's Stellar Cartography laboratory. (SA: "Beta Test")

In 3196, during the Omega-47 crisis, the location of 51 Pegasi 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")

Appendices

Background information

This star system was only mentioned in writing.

Information on this system was derived from 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.

This star system had one confirmed exoplanet as of 2026. This gas giant was named Dimidium and it had the distinction of being the first exoplanet discovered orbiting a main sequence star.

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