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Memory Beta, non-canon Star Trek Wiki

A Class Y or Demon planet was a world with a turbulent atmosphere, saturated with toxic chemicals and thermionic radiation. Demon planets were inhospitable to known humanoid life. (VOY episode: "Demon", ST reference: Star Charts)

History and specifics[]

A malfunction on Vanguard in 2265 resulted in the environmental computers creating a Class Y environment in several sections populated by Humans. The Starfleet Corps of Engineers worked with the station personnel to correct these settings. (SCE eBook: Distant Early Warning)

The Bajoran class N[1] moon Jeraddo became a Class Y "Demon" moon after the tapping of its molten core released toxic gases into the atmosphere. (DS9 - Millennium novel: The Fall of Terok Nor)

A Class Y planet in the Delta Quadrant was inhabited by a mimetic species. In 2374, they reached sentience after an encounter with the crew of the USS Voyager. They duplicated the starship's crew and named themselves the Silver Blood. Until then, Starfleet had believed class Y planets inhospitable to life. (VOY episode: "Demon")

USS Voyager above a class Y planet.

The Silver Bloods' USS Voyager sought out another class Y planet for a layover but were rejected by the Ord'mirit owners. (VOY episode: "Course: Oblivion")

In 2377, the Photonic lifeforms of Iden's Rebellion sought to colonize Ha'Dara, an unclaimed class Y planet that would be unattractive to organic civilizations. (VOY episode: "Flesh and Blood")

By 2378, the Federation was aware that Tholia, homeworld of the enigmatic Tholians, was a class Y planet, and that mimetic species could exist on such worlds. (ST reference: Star Charts)

In 2379, a Talaxian mining vessel and its crew were duplicated following a mining operation on the Silver Blood homeworld. Starfleet also found installations of the Borg Collective on both hot and cold class Y planets. The Borg adapted to the acidic conditions in order to gain valuable materials or for a strategic advantage. (Star Trek Adventures module: Delta Quadrant Sourcebook)

In 2409, the Tholian Assembly seized control of Nukara Prime, a class Y planet in the Nukara star system. (STO website: Season 6 Dev Blog #8)

The barren Kentar I.

An alliance arrived to contest Tholian influence on Nukara Prime. Allied officers wore environmental suits while the Tholians forewent special body suits. The planet's craggy surface included pools of green acid and was otherwise uninhabited. (STO - Under Siege mission: "Tholian Incursion")

In 2410, the Lukari Concordium and the Khitomer Alliance rediscovered the Kentari homeworld in the Huranzi system. Its first moon, Kentar I, was a class Y world. The Tzenkethi had demolished its surface with a protomatter bomb. (STO - New Frontiers mission: "Of Signs and Portents")

In 3064, the Kelpien ship KSF Khi'eth crashed on the class-Y planet Theta Zeta in the Verubin Nebula. It became ground zero for the Burn in 3069, a galactic cataclysm that let to the near-dissolution of the Federation. (DSC episode: "Su'Kal")

In 3189, Theta Zeta, which had been identified as a dilithium nursery, was claimed by the Federation and mining operations commenced. The Federation's new source of dilithium would help reunite former Federation members. The Federation mining vessel Coloma collected enough dilithium at Theta Zeta that USS Discovery-A could begin escorting it to allied worlds and installations. (DSC episode: "That Hope Is You, Part 2")

Class Y worlds[]



Planetary classification
numeric: class 9
alphabetical: class A
class A geothermal
class A gas giant
class B
class B geomorteus
class B gas giant
class C
class C geoinactive
class C reducing
class D class E
class F
class F geometallic
class F geocrystalline
class G
class G geocrystalline
class G desert
class H
class H desert
class H geothermal
class I
class I gas supergiant ("Q'tahL"-class)
class I metallic/silicate
class J
class J gas giant
class J moon
class K
class K silicate/adaptable
class K transjovian
class L class M ("Minshara"-class)
class MZ
class N
class N reducing
class N pelagic
class O class P class Q
class R class S class T class Y

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