An Earth-like planet explored by Enterprise in 2151, where windborne pollen caused dangerous hallucinations among a landing party, and which later sources name after Captain Jonathan Archer.
Archer IV is the uninhabited Minshara-class planet at the centre of the Enterprise episode Strange New World. It is the first such world the NX-01 crew sets foot on, and Archer allows a survey team to camp overnight against T'Pol's advice.
A storm drives the party into a cave, where pollen carrying a hallucinogenic toxin makes Tucker and the others paranoid and convinces them that T'Pol is conspiring with rock creatures. Crewman Novakovich is badly hurt in an emergency transport before Phlox identifies the cause and T'Pol stuns Tucker so the antidote can be given.
The planet is not named in that episode. The name Archer IV comes from a biographical display in In a Mirror, Darkly, and the planet is also the destination mentioned in The Next Generation's Yesterday's Enterprise.