Naiol

Naiol (Coeric [naɪ̯l]) is a planet in the Riėl system. It is the fourth planet from the star, and approximately half as far from it as Seldh.

On Seldh
Naiol is a very bright celestial body in the Seldhen sky, and as such has been noticed by humans on Seldh since prehistory. It has many names across all cultures, and several of them make references to the fact that it is visible soon after sunset / before sunrise, similar to Acharan and Lenduidh.

Geography
Little is known about the geography of Naiol by the people on Seldh, but it is generally believed that the surface of the planet is almost entirely water.

Habitability
Naiol is within the inner edge of the habitable zone around Rieli. Both liquid water and thick atmosphere are thought to be present, and the temperatures across the planet are estimated to be rather tropical. All this makes Naiol potentially very friendly to life.

No direct evidence of life on Naiol has been seen by people on Seldh.

Physical characteristics
Naiol is a large terrestrial waterworld, the fourth planet orbiting the sun Riėl at a distance of 0.6 AU. It has a slightly eccentric orbit and concludes it journey arount its star in ~203 Seldhen days. Although slight, the eccentricity accounts for most of the season variations of Naiol's climate; the planet's axial tilt is very low.

The planet completes a rotation around it's axis in about 40 Seldhen hours.

Naiol's mass is 1.4 times that of Seldh, and is thus capable of retaining a significantly larger atmosphere.

Atmosphere
Naiol's atmosphere is similar to Seldh's, albeit with a higher atmospheric pressure. It is approximately 70% nitrogen, 23% oxygen, 3% helium, with the rest being noble gasses such as argon, as well as trace amounts of carbon dioxide and others. Water vapor averages to about 4% of the atmosphere.

Climate
Owing to the closer distance to the star and it's thicker atmosphere, Naiol is warm planet. Average temperature fluctuates at around 30 °C, reaching higher around the equator and dropping lower in the polar regions.

Naiol does not have polar ice caps.

Wind patterns and precipitation is distributed somewhat evenly across the planet owing to the lack of large land masses.

Geography
95% of Naiol's surface is ocean. The ocean can reach depths of 20kms, though averages 6 km.

A scattering of islands dot the surface. Those islands closer to the equator are scorching hot and uninhabitable to higher life. The same does not hold true for the polar archipelagos.

Biosphere
Naiol has a rich biosphere with incredible biodiversity. The majority of plant and animal life is aquatic. Terrestrial lichen-like organisms are common the the equatorial regions, but higher latitudes host varied terrestrial animal and plant life. Most of the land surface is covered with "tropical" jungles and grasslands.

A lot of the plant life is well adapted to saline environments. Expansive mangroves are common. Several mangrove species concentrate excess salt in specialized leaves that are shed when saturated.

Both terrestrial and aquatic life commonly exhibit bioluminescence. Several aquatic algal species, found near the shores of islands, create stunning displays of forms and color with bioluminescence.

Intelligent life
Naiol is home to a couple million nativized humans. Compared to a typical Seldhen human, Naiol natives are shorter and stockier, as adaptation to the planet's higher gravity.

The human population is limited to the higher latitudes, where temperatures are tolerable for human life.

Non-human intelligence, particularly aquatic, is speculated but not confirmed. Several deep-sea lifeforms exhibit signs of higher cognition, but meaningful contact between them and humans have not been achieved.

Human culture
Settlements such as villages and even towns are common on the hospitable islands. The population is relatively low-tech and deprived of several resources critical for technological development, such as widely available metals. As a result, societies are centered around fishing and agriculture.

Naiol natives comprise a myriad of ethnicities and cultures, many of which are genetically distinct, though not to the extent to inhibit crossbreeding.

Language
There are hundreds of native languages, organized in several language families. They exhibit a wide array of features typical to human languages, but also a couple of weirder features that are surprisingly common of Naiol, such as click sounds, OSV and OVS word order, and a widespread use of infixes and circumfixes.

Some, but not all, Naiol cultures have developed written language. Alphabets, syllabaries and abjads are all present.

Religion
Naiol natives follow several religions, some of which are cosmopolitan and some - specific to certain populations. Most religions seem to be animistic or polytheistic. No major religion is monotheistic.

Naiol religions frequently deifies the ocean and the sun. Another frequent theme is revering auroras - the phenomenon is very common in the polar regions - often in a dualistic comparison to the visually similar yet commonly highly toxic bioluminescent displays of aquatic algae.