Halx Solar System

Specifications

The Sun: Named Halx 21185, it is a G5Vv star with a BV. of +0.674/UB of +0.185. It has a similar mass to Earth's Sun, only 5% smaller in radius. 15% less luminosity than earth's sun.

Planetary Sequence: Referring to the image above, the order from closest to furthest from Halx is: Halx 21185 Ba (named Binary I), Halx 21185 Bb (Binary II), Halx 21185 C (unnamed; barren), and Halx21185 C (named Hyem).

Planetary Geology: Binary I is an oceanic superearth (~94% water) with oxygen saturation levels at 35% (present day Earth is 21%; BI has similar lvls as Earth during the Carboniferous Period).
Binary II became tidally locked after the introduction of a third moon. A planet becomes tidally locked when it's rotation speed matches its orbital period. As a result, the only habitable area is a ring of land the stretches vertically around the planet's middle. This is because the side facing the sun is literally melting, while the cold facing side is frozen solid.
Hyem: An icy mountainous planet furthest from the sun. The mountain regions are massive, significantly larger than Earth's Himalayans. Its distance from the sun makes it nearly frozen solid. The Spire keeps an area within one of the mountain's tarns in liveable condition. The lack of land resource pushes for a significantly smaller population size.