Class R - Rogue
Age: 2-10 billion years
Diameter: 4,000 - 15,000 km
Location: Interstellar space, cometary halos
Surface: May be temperate due to geothermal venting
Atmosphere: Primarily volcanic outgassing
Life-Forms: Non-photosynthetic plants, animal life
Class R planets can generally be in interstellar space or cometary halos. Somewhat smaller than Earth, they range from 4,000 to 15,000 thousand kilometers in diameter. Surface conditions are hostile and ferocious, with violent volcanic activity and carbon dioxide/sulphuric acid clouds swirling in electromagnetic storms of lethal gas and radiation. Temperatures exceeding 400 C make it unsuitable for humanoid life forms. However, the planet doe support non-photosynthetic plants and hardy animal life.
The rogue planet Dakala, which drifts through space, and was used as a hunting ground by a race of telepathic shape shifters in "Rogue Planet" (ENT), is Class R.