Mercaniad

Mercaniad is a star located over 300 parsecs from Federation space.

Mercaniad was very unstable, and effected the orbiting planet Mercan and its inhabitants, the Mercans, in what they call the Ordeal.

When the USS Enterprise (NCC-1701) was catapulted to Mercan in 2269, the Enterprise stabilized the star and stopped the Ordeal.

(TOS novel: The Abode of Life).