Trekipedia

Planet, Class A

Geothermal. Age ranged from 0-2 billion years. Diameter was 1000 to 10,000 km. Typically located in the Ecosphere or Cold Zone of a planetary system. Surface was partially molten, atmosphere was primarily hydrogen compounds. Would eventually cool to become Class C. No native life forms.^[1]

Class-A Planets:

• Gothos

References

• ^[1]STSC: Star Trek: Star Charts