Lethor

Lethor is a minor planet in the Arcturus system, located approximately 1.3 light‑years from the central star. It is a rocky world with a thin, nitrogen‑rich atmosphere and a surface composed mainly of silicate minerals and volcanic basalt. The planet’s orbital period is 284 Earth days, and it rotates on its axis once every 30.5 hours, giving it a relatively short day. Although Lethor has no indigenous life, it supports a sparse population of microbial life forms that thrive in the planet’s subsurface aquifers, an environment that has attracted scientific interest for astrobiology research.

The planet was first observed by the Deep Space 3 survey mission in 2033, and preliminary data indicated rocky composition, cryogenic surface temperatures, and evidence of past tectonic activity. In 2042 a robotic probe, Lethor‑1, was successfully landed on the equatorial plains. The probe’s primary mission was to map subsurface water reservoirs using ground‑penetrating radar and to sample soil for the presence of organic molecules. Preliminary reports showed trace amounts of hydrocarbon compounds, leading to hypotheses about prebiotic conditions.

Lethor is currently a target for further exploration by the Interstellar Exploration Alliance, with proposals to launch a manned research station in the year 2058. Such station would aim to study the planet’s geology, atmospheric chemistry, and potential for future resource extraction. The planet’s name, derived from the ancient Sumerian word for "edge," reflects its position at the boundary of the Arcturus system’s habitable zone.