Overall Description

The Capricorn Zeta System contains an M1 Type V Red Dwarf star orbited by six planets. An asteroid belt lies between the third and fourth orbit. Furthermore, a Trojan dwarf planet follows in the orbit of the fourth planet. The star is much cooler than Sol, meaning temperate planets are much closer.

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Federation Deep Space Station K-9 orbits the Capricorn Zeta star at a range of six Astronomical Units (897,600,000 km), twice the distance out from the outermost planet.

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Planetary Breakdown

Capricorn Zeta I

Class

Class J Dark Blue/Yellow Gas Giant

Radius

47,005 km

Distance from Star

0.043 AU

Mass

59.99 Earths

Surface Gravity

1.11g (no surface)

Length of Year

5.28 Earth days

Length of Day

5.28 Earth days (tidally locked)

Surface Temperature

543.2°C

Surface Composition

Hydrogen, Helium, Sulfur (gas giant)

Water

None

Atmospheric Composition

79% Hydrogen, 16% Helium, 4% Carbon Dioxide, 1% Sulfur Dioxide

Atmospheric Pressure

479.9 atm

Moons

None

Population

None

Notes

Capricorn Zeta I is a "Hot Jupiter" gas giant. It is tidally locked to the star and slowly losing Hydrogen as a result of its extreme proximity.

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Capricorn Zeta II

Class

Class M Terrestrial Planet

Radius

6,631 km

Distance from Star

0.191 AU

Mass

0.76 Earths

Surface Gravity

0.71g

Length of Year

49.46 Earth days

Length of Day

549.4 Earth days (extremely slow)

Surface Temperature

16.1°C

Surface Composition

Silicates with a small metal core

Water

21% liquid surface water

Atmospheric Composition

82% Nitrogen, 16% Oxygen, 2% Carbon Dioxide

Atmospheric Pressure

0.92 atm

Moons

None

Population

50

Notes

Capricorn Zeta II houses an outpost of scientists studying life on the planet. The extremely slow rotation of the planet means one side is very hot and the other very cold, with a temperate band along the twilight area. The outpost is equipped with engines permitting it to relocate; it moves every 50 days to remain in the temperate zone. Plant life appears to go dormant in extreme heat or cold while animal life hibernates or migrates.

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Capricorn Zeta III

Class

Class F Geocrystalline Terrestrial Planet

Radius

5,725 km

Distance from Star

0.367 AU

Mass

0.93 Earths

Surface Gravity

1.16g

Length of Year

131.73 Earth days

Length of Day

760.8 Earth days (extremely slow)

Surface Temperature

-46.4°C

Surface Composition

Iron-nickel with a large metal core

Water

54% ice surface water

Atmospheric Composition

77% Nitrogen, 18% Methane, 5% Argon

Atmospheric Pressure

1.86 atm

Moons

One (iron-nickel with a large metal core, radius of 1,700 km, gravity of 0.3g, no atmosphere)

Population

750 (across planet, moon, and nearby asteroid belt)

Notes

Capricorn Zeta III and its moon are very cold but contain a wealth of mineral resources, including diburnite and dilithium. A fully contained colony exists, supporting mining operations on the planet, the moon, and across the asteroid belt.

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Asteroid Belt

Class

Asteroid belt

Radius

N/A

Distance from Star

0.688 AU (average)

Mass

0.0008 Earths

Surface Gravity

N/A

Length of Year

232.19 Earth years

Length of Day

N/A

Surface Temperature

N/A

Surface Composition

Mostly Silicates

Water

N/A

Atmospheric Composition

N/A

Atmospheric Pressure

N/A

Moons

N/A

Population

N/A

Notes

Thousands of asteroids of all sizes populate the Capricorn Zeta asteroid belt. None are large enough to support a population. Workers from the colony on Capricorn Zeta III frequently seize asteroids for mining.

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Capricorn Zeta IV A

Class

Class I White/Red Gas Giant

Radius

25,865 km

Distance from Star

1.132 AU

Mass

17.32 Earths

Surface Gravity

1.05g (no surface)

Length of Year

338.13 Earth years

Length of Day

26.4 Earth hours

Surface Temperature

-142.7°C

Surface Composition

Hydrogen, Helium, Ammonia, Sulfur (gas giant)

Water

Ices

Atmospheric Composition

83% Hydrogen, 10% Helium, 6% Ammonia, 1% Sulfur Dioxide

Atmospheric Pressure

10.39 atm

Moons

11 (2 larger ones, with radii of 1,211 km and 235 km, but the rest are captured asteroids under 100 km in radius)

Population

None

Notes

Capricorn Zeta IV is an unremarkable gas giant. Its larger moons are occasionally visited by mining colony expeditions for surveys.

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Capricorn Zeta IV B

Class

Class D Barren Trojan Planetoid

Radius

434 km

Distance from Star

1.132 AU

Mass

0.000035 Earths

Surface Gravity

0.007g

Length of Year

338.13 Earth years

Length of Day

10.8 Earth hours

Surface Temperature

-167.0°C

Surface Composition

Ices

Water

Ices

Atmospheric Composition

None

Atmospheric Pressure

None

Moons

1 (275 km in radius, almost a double planet)

Population

None

Notes

Capricorn Zeta IV B is a Trojan, meaning it follows the gas giant Capricorn Zeta IV A in its orbit around the star, 753,130 km behind it. Its moon is a significant percent the radius and mass of the planetoid, resulting in the moon’s orbit heavily affecting the planetoid itself, almost to the point where they orbit each other.

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Capricorn Zeta V

Class

Class I Light Blue/White Gas Giant

Radius

26,101 km

Distance from Star

1.571 AU

Mass

14.38 Earths

Surface Gravity

0.86g (no surface)

Length of Year

713.63 Earth years

Length of Day

9.6 Earth hours

Surface Temperature

-158.9°C

Surface Composition

Hydrogen, Helium, Methane (gas giant)

Water

Ices

Atmospheric Composition

85% Hydrogen, 9% Helium, 6% Methane

Atmospheric Pressure

17.25 atm

Moons

2 (72 km and 800 km in radius; the planet also has a thin icy ring)

Population

None

Notes

Capricorn Zeta V is a small gas giant with a surprisingly small number of moons, likely due to the gravitational effects of the larger fourth and sixth planets.

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Capricorn Zeta VI

Class

Class I Dark Blue Gas Giant

Radius

35,215 km

Distance from Star

2.928 AU

Mass

72.31 Earths

Surface Gravity

2.37g (no surface)

Length of Year

1,166.71 Earth years

Length of Day

12.3 Earth hours

Surface Temperature

-186.7°C

Surface Composition

Hydrogen, Helium (gas giant)

Water

Ices

Atmospheric Composition

95% Hydrogen, 5% Helium

Atmospheric Pressure

3.62 atm

Moons

17 (smallest is 14 km in radius, largest is 1,699 km in radius; the planet also has a thin icy ring)

Population

None

Notes

Capricorn Zeta VI is the outer system "Sweeper" gas giant; its gravity helps divert comets, asteroids, and other objects away from the inner system.

There is an unmanned listening post on the eleventh moon, which helps monitor transmissions in Klingon space.