Antitarra is a standard hydrogen-helium gas giant with traces of ammonia. Hydrocarbons in the atmosphere lend it a distinct brown tint.
- Survey: UNC: Valuable Minerals: Gas Deposit ×1 (Helium-3)
- Antitarra is too small to be a "standard hydrogen-helium gas giant" (William Hubbard, The New Solar System 4th ed, 1999; p. 194). It is more likely a dense "ice giant" like Neptune or Gliese 436 b.