Eirene

Eirene is the 4th planet from Beta Virginis. Eirene is very similar to Earth, both because of its composition and climate, and because it is the only planet in the system to possess life on its surface. Eirene's atmosphere is similar to Earth's during the Devonian period but with a higher moisture content, consisting of about 15 percent oxygen and 0.38 percent CO2. The planet's hot and humid tropical climate creates large clouds which take up most of the sky. The tropical climate also allows strong hurricanes to form almost constantly.

Eirene has a biological ecosystem made up of single-celled and primitive multi-celled organisms. Life on Eirene has evolved to be similar to the life found on Earth, the organisms have a DNA equivalent, PNA (Peptide nucleic acid), and an RNA equivalent, ANA (arabinose nucleic acid). The PNA and ANA strands use 4 bases, d5SICS, dNaM, Pyrrole-2-carbaldehyde, and Imidazole-4-carbaldehyde. Living beings on Eriene also have an ATP alternative in the form of GTP, and they have evolved Non-cyclic Photophosphorylation and Oxidative Phosphorylation with nitrate as a terminal electron acceptor to produce GTP. Plant and algae-like organisms have migrated onto the coasts of Eirene, with moss reaching further inland. Beta Virginis' greater output of UV rays and the thinner ozone layer on Eirene causes a greater dose of UV radiation on the surface. Plants near the equator have higher amounts of anthocyanin, flavonoid, and xanthophyll pigments which protect the plants from ultraviolet light and give them a reddish hue.

Eirene had a human colony established on it to both study the ecosystem present, and to act as the primary launch point for the inner Beta Virginis system. Though launching rockets often on Eirene is heavily discouraged to not disturb the ecosystems surrounding the launch site.