In 2152, the starship Enterprise was the first Earth ship to research a red hypergiant at close range. It was nearly a billion kilometers in circumference and was not expected to go supernova for another one hundred or two hundred years. (ENT: "Cogenitor").

Precise definitions vary, but all astronomers agree that hypergiants are the most massive and luminous type of star. They are on the verge of instability with masses of up to about 100 solar masses, strongly developed large-scale atmospheric velocity fields, excessive mass loss, and extended circumstellar envelopes. Hypergiants can survive only a couple of million years or so before exploding as supernovae and, theory insists, leaving behind black holes. Because of their high masses, the lifetime of a hypergiant is very short in astronomical timescales, only a few million years compared to around 10 billion years for stars like the Sun. Because of this, hypergiants are extremely rare and only a handful are known today. VY Canis Majoris (VY CMa) is a red hypergiant star located in the constellation Canis Major. It is the largest known star and also one of the most luminous known. It is located about 1.5 kiloparsecs (4,900 ly) away from Earth, and has a radius of between 1800 to 2100 solar radii.

Only about a dozen others are known in our galaxy, including Eta Carinae, P Cygni, and Rho Cassiopeiae. S Doradus is a hypergiant in the nearby Large Magellanic Cloud.