Keryn

A view of Keryn from space.

Named after the concept of its dark side symbolising dark hair, as the name Keryn means 'black-haired one'.

Keryn is the fourth furthest planet from the star, it is the fifth largest planet in the Kerynite system by diameter, and the third-most-massive planet. Keryn is 1.593 times the size of Earth and around five times as massive, making Keryn a super-earth.

Due to the close proximity to its star Keryn orbits once every 35.357 days, as a result of being tidally locked it does not have a day-night cycle like Earth does. Keryn has four tidally locked asteroid moons.

The atmosphere is composed primarily of carbon dioxide and oxygen, along with traces of sulphur dioxide, nitrogen, argon, water, and neon. The immense amount of carbon dioxide leaves the atmosphere unbreathable for humans.

Spite its inhospitality to humans, native lifeforms make this gem their home. The abundance of life makes Keryn a truly special place.

## The Kerynite System

A class M0.8 V red dwarf star hosts the solar system. Red dwarves are amongst the smallest and coldest stars in the known universe, their habitable zones are closer to the centre and you can expect to find planets orbiting very close to the red dwarf.

Due to their close proximity to the star it is common for the inner planets to be tidally locked to the red dwarf, meaning that one side of the planet always faces the star while the other side is in eternal darkness.

Keryn is one of the two inner planets that has been tidally locked by the stars grip.

**Below is the list of data and information about the Kerynite star system:**

* Class M0.8 V star.

Type: Star / Temperature: 3472.9 Celsius / Luminosity: 0.027611

* Planet 01. Tidally locked: No

Type: Hot Selena / Temperature: 369-412 Celsius / Diameter: 5557.8 km / Mass: 0.051346 / Gravity: 0.26988 g / No. of Moons: 1 / Distance from Star: 4.4-5.1 million km

Orbital period: 2.996 days

* Planet 02. Tidally locked: Yes

Type: Hot Desert / Temperature: 217-255 Celsius / Diameter: 7210.118 km / Mass: 0.25162 / Gravity: 0.78581 g / No. of Moons: 1 / Distance from Star: 7.8-8.8 million km

Orbital period: 6.630 days

* Urantica Tidally locked: No

Type: Warm gas giant / Temperature: 53-83 Celsius Diameter: 151336.734 km / Mass: 1.367 / Gravity: 3.0799 g / No. of Moons: 15 / Distance from Star: 0.10-0.11 AU

Orbital period: 18.231 days

* **Keryn** Tidally locked: **Yes**

Type: Temperate terra with life / Temperature: 20-28 Celsius / Diameter: 20298 km / Mass: 5.7822 / Gravity: 2.2785 g / No. of Moons: 4 / Distance from Star: 0.16-0.17 AU

Orbital period: 35.357 days

* Tigrundito Tidally locked: No

Type: Cool gas giant / Temperature: -68 to -79 Celsius / Diameter: 139919.9 km / Mass: 12.587 / Gravity: 33.175 g / No. of Moons: 42 / Distance from Star: 0.28-0.32 AU

Orbital period: 85.548 days

* Planet 06. Tidally locked: No

Type: Cold ice world / Temperature: -120 to -124 Celsius / Diameter: 3405.2995 km / Mass: 0.01138 / Gravity: 0.15933 g / No. of Moons: 2 / Distance from Star: 0.60-0.64 AU

Orbital period: 254.512 days

* \*\*\*\*\*ASTEROID BELT\*\*\*\*\*
* Planet 07. Tidally locked: No

Type: Cold gas giant / Temperature: -167 to -175 Celsius / Diameter: 107906.9 km / Mass: 0.20814 / Gravity: 0.92241 g / No. of Moons: 52 / Distance from Star: 1.07-1.23 AU

Orbital period: 1.762 years

* Planet 08. Tidally locked: No

Type: Frozen ice world / Temperature: -188 to -192 Celsius / Diameter: 10459.9078 km / Mass: 0.29215 / Gravity: 0.43354 g / No. of Moons: 15 / Distance from Star: 1.99-2.19 AU

Orbital period: 4.319 years

* Planet 09. Tidally locked: No

Type: Frozen titan / Temperature: -199 to -200 Celsius / Diameter: 17926.7198 km / Mass: 1.3888 / Gravity: 0.70168 g / No. of Moons: 20 / Distance from Star: 3.34-3.45 AU

Orbital period: 8.961 years

* Planet 10. Tidally locked: No

Type: Frozen ice world / Temperature: -220 to -222 Celsius / Diameter: 26136.39 km / Mass: 6.7372 / Gravity: 1.6013 g / No. of Moons: 0 / Distance from Star: 5.72-6.61 AU

Orbital period: 21.897 years

* \*\*\*\*\*ASTEROID FIELD\*\*\*\*\*

The star system is about 616.88 light years away from Earth, thanks to the distance and Keryns star being a red dwarf it cannot be seen by the naked eye from Earth. A sophisticated telescope would be required to find and identify the system.

The furthest planet from the star is about 5.72-6.61AU in distance, in our Solar system that distance would reach out somewhere between Jupiter's and Saturn's orbit. By inspecting and judging the relative distance from the star to its furthest asteroids, the total size of the Kerynite system would be an estimate of approximately 25-35AU.

## History

    The Kerynite Star System formed at least 200 million years after our Solar System was formed, making Keryn's age at an estimate of 4.3 billion years.

4.3bya: When Keryn first formed the star system was constantly bombarded by asteroids, present bodies of water made from craters suggests that large extra-terrestrial bodies collided with the planet. Large collision impacts were an occasional occurrence but have contributed to the planets mass and composition of today.

4.3-1.5bya: 4 wandering asteroids were captured and became satellites, Keryn then became a tidally locked planet due to tidal friction.

4.0bya: Volcanism was at a peak which allowed for a thicker atmosphere, Keryn used to more closely resemble present-day Venus. Deep in the oceans the first signs of life emerged in hydrothermal vents, extremophile micro-organisms thrived.

3.8mya: Keryn's magnetosphere weakened because of solar flares, its resulting exposure of its atmosphere prevented the planets possible transition from a Terran (earth-like planet) to a Neptunian planet (gas giant).

1.0bya: Multicellular marine life evolved, by this time the permanent acid storm eroded the lands below to form a vast ocean making the planet look very similar to today. An increase in oceans allowed for and resulted in global distribution of life.

500-300mya: First plants and terrestrial life, they were largely restricted to coastal regions. Keryn's equivalent of the Cambrian explosion also occurred at this time.

250mya: Diverse plant species spread throughout the suitable areas of the planet, arthropods and terrestrial life find a way to make a permanent home on land.

100mya: Volcanic super-eruptions caused CO2 and SO2 levels to skyrocket, this resulted in a mass-extinction. An SO2 synthesizing algae saved the surviving species, making it one of the most important lifeforms in the eco-system. Dinosaur-like creatures now take the stage as the dominant species.

    Present: Keryn as we know it today. The eco-system regulates the volcanic emissions by cleaning up the air, current situation is stable with life steadily growing more complex and thriving.

When the Kerynite star system first formed all manner of celestial bodies bombarded one another, on average the bodies that later became planets were bodies that absorbed the most asteroids. When there were no more wandering asteroids left to absorb (other than the remaining ones in the asteroid belts), the resulting planets with significant gravity created atmospheres.

Keryn's orbit is sandwiched between two gas giants, this situation significantly reduced the probability of extra-terrestrial impacts allowing for life to evolve without much threat of mass-extinction. When comparing Keryn to its gassy neighbours it has the second largest mass and the weakest largest gravity.

Originally Keryn was going through a slow but steady transition from a Venusian-like planet to a gas giant, its magnetosphere was at its strongest when it was first formed and as a result its atmosphere was thicker. As time wore on solar flares receded the magnetosphere and consequently thinned the atmosphere, this thinning terminated Keryn's transition into a gas giant allowing for life to survive. Luckily for the life evolving on the planet its magnetosphere still offers enough protection from radiation.

## Physical Description

### **Atmosphere**

The abundance of CO2 in the atmosphere and widespread volcanic emissions are its key characteristics, it shares the most resemblance with the Venusian atmosphere which is also very high in CO2. If you breathed in a sample you will notice that it has a sharp acidic and eggy odour, like eggs in soda water.

Atmospheric pressures at sea level are three times as great as Earths measuring at 3.44 atm, which is within the limits of human tolerance but not without major discomfort or risk of life. Its richest layer is 2.41km high with the total atmospheric height of 27.54km, the air density is 5.9366kg/m3 (Earths value 1.2929kg/m3). Compared to our Earths high and spacious atmosphere, Keryn's is low-lying and compact.

The shallowness and thickness of Keryns atmosphere is attributed to its high-gravity trapping more gasses and the abundance of CO2 making Keryns atmosphere heavier than Earths.

Consequently its low-lying sky makes altitude temperature differences much more pronounced, air is much warmer at lower altitudes but rapidly becomes cold uphill. These glaring temperature differences contribute to the katabatic winds, high-density winds that carry air downhill under the power of gravity.

Sulphur dioxide from the volcanoes has a strong cooling effect on the planet, the smoke and other aerosols from volcanic eruptions reflecting the sunlight. Keryn has lots of sulfur in its atmosphere and has high-altitude ice clouds, which is something that does not occur on earth.

Life plays an important role by altering the atmosphere. Life evolved oxygenic photosynthesis at some point 2.4 billion years ago, creating the primarily CO2-O2 atmosphere of today. This new presence of oxygen formed the ozone layer which made conditions more hospitable to life by filtering out the harmful UV rays, it is about 50% thicker than our Earths ozone layer.

Due to the significant presence of oxygen the air is flammable and as a result fires do exist on Keryn, the abundance of fuel produces larger blazes that last longer than Earths.

> The images above shows our Earths atmosphere (right image) being compared with Keryns atmosphere (left image). Click on a image for a better view and readability.
>
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**Below is a list of data about the atmospheric composition:**

```
Carbon Dioxide (CO2)  = 90.5%             3.11 atm

```

```
Oxygen (O2)           = 9.23%             0.317 atm

```

```
Sulphur Dioxide (SO2) = 0.241%            0.00829 atm

```

```
Nitrogen (N2)         = 360ppm            0.00124 atm

```

```
Argon (Ar)            = 2.39ppm           0.0000236 atm

```

```
Water (H2O)           = 2.09ppm           0.0000207 atm

```

```
Neon (Ne)             = 0.106ppm          0.00000105 atm

```

### **Geography**

    Much of the planet is rocky with oceans covering less than 50% of the surface. Keryn has two significant continents that are split by the ocean that cuts through, this makes identifying the north-south hemispheres easy.
The harsh weather resulting from tidal locking has had a big effect on the planets surface, erosion is much more powerful than on Earth and is the primary influence on the planets geography.

    The region that faces the star has acidic storms that never end which results in erosion, consequently the altitude of the star-facing region is much lower than the region that has no starlight and weather. The high-altitude region that surrounds the low-altitude region has a much thinner atmosphere, much less precipitation and has much less erosion as a result.

Because of the erosion there are no large islands in the star-facing part of the ocean except for a few young volcanos. Big islands can only be found in parts of the ocean that are further away from the star-facing region as can be seen in the images.

Another defining feature of Keryns geography are the active volcanoes that dot the landscape, spewing carbon and sulphur dioxide into the atmosphere. Due to the high gravity the most common type of volcanos found on Keryn are shield types, they are very big and broad but with less steep slopes than other types. A good example of a shield volcano is the Hawaiian volcano called 'Mauna Loa', like the volcanos on Keryn it is very large but not steep.

At least more than half of the volcanoes are located in the oceans, evidently this would assume that there is widespread geological activity within the oceans with unstable and dynamic seafloors. The area with the most volcanoes relative to area is the west part of the ocean and is predictably the most volcanically active.