Hetemit IX
Hetemit IX was the formerly inhabited ninth planet in its star system. It was a class M world, with 47% of its surface covered by water. It had a mantle composed of molten iron-sulfur alloy. The planet was regularly swept by dangerous ion storms. ()

Astronomical data

The planet was located at coordinates 2723.5389. It had a rotation period of 22.9 hours and a revolution period of 537.2 solar days. Its mass was estimated to be 6.3402 kilograms and its age at 6.1 billion solar years. The atmosphere was composed of 71% molecular nitrogen, 26% molecular oxygen, 1.9% argon, 0.3% carbon dioxide, and 0.2% nitrous oxide, with trace amounts of methane and carbon monoxide. The mean surface temperature was 12.6 degrees Celsius. ()

History
Hetemit IX was once home to an Illyrian colony that sought to join the Federation. Due to the Federation's prohibition on genetic engineering, the colonists were conducting research into reversing their genetic modifications. The population eventually succumbed to a light virus that induced a suicidal attraction to light. However, some of the afflicted colonists ran into ion storms, where charged storm particles unexpectedly bonded with their electromagnetic patterns and transformed them into beings of plasma.

In 2259, the  visited Hetemit IX as part of a standing Starfleet mission to investigate the fate of the colony. Some members of its away team were infected by the light virus on the planet and caused an epidemic on the Enterprise, which was resolved thanks to Number One's Illyrian genetic modifications. Meanwhile, Captain Christopher Pike and Lieutenant Spock were temporarily stranded on the surface by an ion storm, during which the surviving colonists in their plasma forms protected them from the storm's effects. The former Illyrians then directed them to a record of what they had been trying to accomplish. ()

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