Murray-Callahan

Geography

Location

Murray-Callahan is located some 2.62 lightyears from the Sirius system, in the general direction of Kapteyn's Star. It is moving away from Sirius at an unusually low relative velocity, indicating that this planet likely had a close gravitational encounter with that stellar binary in the relatively recent past —it is even possible that Murray-Callahan was once a Sirian planet.

Structure

This rogue planet is very unusual, having a dense nitrogen and hydrogen atmosphere kept warm enough to avoid freezing by geothermal energy. Below this thick blanket of gases lies a carbon-rich, icy surface, with pockets of liquid methane bubbling up around geothermal "hot spots." Below the icy crust is a mantle of liquid hydrocarbons and ammonia, which is in turn wrapped around a dense, metal-rich core heated by radioactive decay. This phenomenon has led scientists to suspect that Murray-Callahan is a relatively young planetoid, lending weight to the hypothesis that it was once part of the Sirius system.

Ecology

Murray-Callahan is unique among all rogue planets in one particular respect: it hosts native life in its geothermal methane pools. These organisms are simple unicellular microbes with exotic, ultra-low-temperature biochemistry that utilizes nitrogen as a major molecular component (in addition to carbon). The origins of the organonitrile microbiota are unknown, but studies suggest they may have arisen on the planet itself millions of years ago, when it still had a sun.

Habitation

The Ecological Research and Preservation Agency has declared Murray-Callahan as a Level VI restricted object due to its scientific value, and maintains an automated perimeter out to 2 light-hours. The planet has zero surface structures whatsoever, and even the orbital station is small and strictly managed, having only forty organic personnel at all times (plus two resident AIs. Exploration of this unique planetoid is done exclusively with remote and autonomous drones.