Class Y planet

Class Y
Classification:	Demon
Age:	2-10 billion years
Diameter:	10,000-15,000 km
Location:	Hot Zone/Ecosphere/Cold Zone
Surface:	Temperatures exceeding 500°K
Atmosphere:	Saturated with toxic chemicals and thermionic radiation
Lifeforms:	crystalline, mimetic (biomimetic)

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 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: Under Siege: 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

• Ha'Dara, Delta Quadrant
• Kentar I, Huranzi system, Ferenginar sector, Alpha Quadrant
• Nukara Prime, Boreth sector, Beta Quadrant
• Ord'mirit planet, Delta Quadrant
• Silver Blood homeworld, Vaskan sector, Delta Quadrant
• Theta Zeta, Verubin Nebula
• Tholia, Alpha Quadrant
• unnamed class Y planets:
  • Borg worlds

Appendices

Connections

Planetary classification
numeric:	class 9 ("Q'tahL"-class)	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 ("Demon"-class)

Appearances and references

Appearances

• VOY episode: "Demon" (first appearance)
• VOY episode: "Course: Oblivion"
• VOY episode: "Flesh and Blood"
• ST reference: Star Charts
• STO website: Under Siege: Season 6 Dev Blog #8
• STO - Under Siege mission: "Tholian Incursion"
• STO - New Frontiers mission: "Of Signs and Portents"
• Star Trek Adventures module: Delta Quadrant Sourcebook
• DSC episode: "Su'Kal"
• DSC episode: "That Hope Is You, Part 2"

External link

• Class Y planet article at Memory Alpha, the wiki for canon Star Trek.