Ephesus III is at ~4 AU. Analysis of data from a robotic Imperial Scout Service probe six years ago flagged the world for human investigation due to the disparity between the apparent mass of Ephesus III and its surface gravity. Though surface gravity is near 1 G, the mass of the planet is only 86% that of Earth.
III is a world of questions. Its size is too small for the mass it exhibits. It has no organic life upon its surface, yet there is free oxygen. There are features, like the Escarpment, that are too regular to be caused by tectonic forces, yet show no sign of construction. There are relics and edifices, like the Observatories, that are obviously constructed, yet show no signs of tools or workers. There is no chlorophyll or other organic compounds, yet there is a rich microbiota upon its surface.
Further investigation also revealed that the atmosphere contains a rather high level of oxygen in a non-volcanically active, non-chlorophyll bearing biosphere. There is no open water on III, though sub-surface icecaps at the poles have been postulated from the planetary scan data. With care, humans can exist on the surface of III without pressure suits or domed facilities, using daysuits and related equipment.
A Company analysis team was flagged to study the probe data for Ephesus III due to the gravity-mass mismatch and the presence of free oxygen. Their preliminary work indicates that III, at some time in the past, was the target of an extensive terraform operation with the world being wrecked three million years in the past.
Ephesus III's surface is a horrible jumble of landforms, mismatched rock types and strata. Though no sign of current tectonic or geological activity has been noted, the formation ages of exposed rocks vary from one million years ago to three hundred million years. Weathering patterns are equally varied. In some exposed faces of the slot canyons of the Escarpment, tiny marine fossils can be found, dating to three million years ago. These are the remains of the nascent ecosystem that was evolving when Ephesus III was smashed into rubble. The exposed surface has weathered since then, but all of the previous planetary water and atmosphere was lost. A new, different, atmosphere has regenerated and new sediment has been laid down.
Life forms include: