Introduction
Tælostri is a hydrocarbonic moon, the third of 5 consecutive ones orbiting a gas giant named Thauniash. It is special for its gorgeous blue colour, caused by a significant amount of liquid oxygen and nitrogen in its oceans. An amount of methane is also dissolved in the oceans, giving them a purple tinge. It was discovered in 6115 CE.
Properties
Tælostri, being extremely cold, is obviously made of ice, for a large part of it at least. This reduces its density to a mere 3.0023 grams/cm3. The ice itself though, is made up of multiple components, such as hydrocarbons and ammonia, but mainly water. Surprisingly, there are no organic compounds on Tælostri.
Tælostri's atmosphere is very hazy, consistent with expectations for similar worlds. Methane and gaseous oxygen colour it a brilliant blue, just like its oceans. Brown clouds of methane and other compounds dot the moon, commonly raining down liquid oxygen and methane onto the surface.
Surroundings
Tælostri is in a binary system composed of two F-type main sequence stars, one F0V and the other F9V, which complete an orbit around one another every 62.33 years. Thauniash, Tælostri's parent gas giant, lies far from the barycentre of the binary, revolving around the two suns in around 1248 years. Tælostri revolves around Thauniash every 15.55 days.
Thauniash
Thauniash, the parent planet of Tælostri, is a ringed gas giant. Fierce weather has constantly troubled it for the last few million years, with winds raging at almost 2000 km/hr and a storm known only as 'the eye of Thauniash'. The planet's colouring is similar to Tælostri's, having blue and brown bands across a relatively white background, and a violet atmosphere. Just like Tælostri, Thauniash has a significant amount of oxygen in its atmosphere, leading to carbon monoxide clouds and condensing carbon dioxide, which accumulates in the planet's interiors. Thauniash's rings were formed by interactions from past moons, and are largely composed of rock.
The other moons
Thauniash has 67 moons, 13 of which are major moons. Among the 13, 5 of them are hydrocarbonic worlds, which is clearly a lot. It is still unknown how so many similar worlds could accumulate around one gas giant.
Uses
Oxygen is sometimes mined from Tælostri and distributed to other worlds. However, this is usually done on the two outer moons of Thauniash, because they have cloud cover that obscures the thinning sea levels, while Tælostri has less cloud cover.