A stellar cluster or star cluster was a group of stars held together by gravity. In 2151, shortly before passing out after being shot by Suliban on Rigel X, Jonathan Archer thought he should be mapping star clusters or making peaceful first contacts, not get into firefights. One year later, he shared this memory with Tessic. (ENT: "Marauders") The Federation established a colony in the Strnad system inside a stellar cluster of over 3,000 stars in 2364. This cluster was claimed by the Edo God. (TNG: "Justice" )