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Zeta Reticuli system is a conjectured planetary system of the binary star system Zeta Reticuli, located 39.2 light-years away in the constellation Reticulum in the caelregio Selachimorphus.


Zeta Reticuli is comprised of two Sun-like stars orbiting around the center of mass. The two stars are separated by at least 3750 AU and orbital period of 170 millennia or more. Around ζ2, there is a debris disk at 100 AU. Both stars are slightly less massive, smaller, and dimmer than our Sun.

Planetary system[]

Class Semimajor axis (AU) Eccentricity Orbital period (yr) Radius Mass Density (g/cm3) Gravity (g) Rotation period (d) Surface temp (K)
Ab SBDEbH 0.3927 0.34263 0.2515 0.8156 R 0.5003 M 5.084 0.752 39.3634 356
Ac CtEcC 0.6219 0.15201 0.5012 0.7515 R 0.2196 M 2.853 0.389 18.5625 378
Ad BEaG 0.8185 0.51433 0.7566 1.4510 R 2.1748 M 3.926 1.033 6.1440 292
Ae SiOEbG 0.8185 0.51433 0.7566 0.9715 R 1.0167 M 6.115 1.077 5.4250 299
Af ICtEaM 1.2932 0.24279 1.5028 0.4102 R 0.0801 M 6.395 0.476 −161.0374 217
Ag GJaA 4.2657 0.48672 9.0026 1.1469 RJ 4.5727 MJ 4.015 9.168 2.0703 362
Bb CtEcH 0.3571 0.02516 0.2151 0.2693 R 0.0459 M 12.965 0.633 45.8231 411
Bc OEaC 0.7053 0.08676 0.5970 2.4417 R 6.5938 M 2.498 1.106 1.2534 376
Bd BEaM 1.4653 0.38129 1.7875 1.4172 R 4.1506 M 8.041 2.067 2.1599 366
Be IEbA 4.2063 0.18730 8.6940 0.8567 R 0.8804 M 7.722 1.200 1.1310 182
Bf MBEcJ 6.6298 0.63763 17.2036 0.5592 R 0.1072 M 3.382 0.343 7.8031 97

Zeta Reticuli has 11 planets, six orbit ζ1 and five orbit ζ2. All but one are terrestrial with masses ranging from 0.08 M to 6.6 M. The planets take between 11 weeks to over 17 years to orbit their respective star at semimajor axes ranging from 0.36 AU to 6.63 AU. The planets have eccentric orbits due in part to gravity of the other star in the binary system. An average eccentricity of this planetary system is 0.325, considerably higher than most planetary systems with at least four planets, but not as high as the 61 Cygni system (0.367) and 70 Ophiuchi system (0.417).

Zeta Reticuli Ab[]

Zeta Reticuli Ab is the closest planet to ζ1 Ret, orbiting at a Mercury-like orbit with a 92-day orbital period. The planet has half the mass of Earth and is correspondingly smaller than Earth. The planet's diameter is 10.4 megameters, which is over 45 the size of Earth. It is slightly less dense than Earth and two other solar terrestrial planets at a value of 5.08 g/cm3. The surface gravity is 75% as strong as Earth's, meaning an average adult human would weigh 113 pounds on this planet compared to 150 pounds on Earth.

Zet Ret Ab is a sulfur planet with the surface temp of 180°F. It's atmosphere is made of sulfur compounds, mostly sulfur dioxide, and the planet appears yellow from space. Its rotation is slow, taking 3913 days to rotate once.

Zeta Reticuli Ac[]

Zeta Reticuli Ac is a sub-Earth, massing 22% of the amount of mass Earth contains. It is three-quarter the size of Earth and this rocky planet's density is low, at just 2.85 g/cm3, a bit less dense than the Earth's Moon. Its gravitational strength is similar to sub-Earths in our solar system, Mercury and Mars.

It orbits at an average distance of 0.62 AU and takes half a year or 183 days to revolve around the star once. Its orbital eccentricity is the third lowest among all the planets in this system at 0.152.

The planet has a tenuous atmosphere made mostly of CO2 and the rotation period is 18.6 days. The surface temp is 220°F.

Zeta Reticuli Ad[]

Zeta Reticuli Ad is a planet bigger and more massive than Earth, orbiting in the middle of the habitable zone, but its eccentricity would take the planet outside of the HZ. The planet–star distance varies from 0.40 to 1.24 AU and would experience wild temperature swings throughout its 27613-day orbit. The surface temperature would swing from −22°F to 267°F. Due to this, complex life would be having hard time to form.

This planet has mass 2.175 Earth masses, barely classifying this as super-Earth. It has a diameter of 18.5 megameters, 45% bigger than Earth. Its density is 3.93 g/cm3, which is the same as Mars', and has surface gravity about the same as Earth's at 1.03 g. The planet takes 6.14 days or about 147 hours to rotate once on its axis.

Zeta Reticuli Ae[]

Zeta Reticuli Ae share the orbit with Zet Ret Ad that it orbits 180° from that planet. When sharing orbit, semimajor axes, orbital periods, eccentricities, and other orbital elements are identical between two or more planets.

The physical properties of this planet is quite different than the other planet of the pair. Its mass and size is very similar to Earth, plus its surface gravity and surface temperature. Its rotation period is 5.43 days or 130 hours.

Home of the grays[]

According to Betty and Barney Hill, this planet is home to the grays, who occasionally come to Earth in UFOs and people sometimes reported seeing them, especially during alien abduction. I do believe in their story, and speculate that almost every UFO aliens coming to Earth came from this planet. Zeta Ret Ae is the gray's homeworld, and civilizations occupy a shade less than half (48%) of the planet's surface, almost exclusively as cities, almost classifying Zeta Ret Ae as a city planet. Although 67% of the planet's surface is covered in oceans of water, 33% of the city area occupy the oceans, mainly submarine.

Zeta Reticuli Af[]

Zeta Reticuli Af is a small planet just 8% the mass of Earth and three quarter the mass of Mars. The planet's surface is cold at a temp of −70°F, causing the surface to be covered in ice. Due to this, the planet appears white from space.

The planet rotates in the opposite direction to its orbit and it takes very long to make one spin. It takes roughly 161 days. It takes about 18 months to orbit once around the star at a distance ranging from 0.98 to 1.61 AU.

Zeta Ret Af sizes 5.23 megameters, which is about 45 the size of Mars, and with the mass a bit lower than Mars', the density is 6.4 g/cm3, compared to 3.94 g/cm3 for Mars. Its gravitational strength is nearly half that of Earth's and bit stronger than Mars'. An average adult human would weigh 71 pounds instead of 150 as it is on Earth.

Zeta Reticuli Ag[]

Zeta Reticuli Ag is a superjovian planet over 412 times more massive than Jupiter. It sizes at 87 that of Jupiter and has density in the range of terrestrial planets at 4 g/cm3. Its surface gravity is close to 312 times stronger than Jupiter, meaning an average adult human would weigh as much as 1375 pounds on this planet.

This planet orbit at an average distance of 414 AU and takes nine years to orbit its sun. Due to its high eccentricity typical of planets in this system, it varies in distance from 215 AU to 613 AU. The planet rotates very quickly, typical of massive planets. However, this planet is an exception as it takes over two days or nearly 50 hours to complete its rotation.

Zeta Ret Ag has a temp of 191°F, at 1-bar layer. At this temp, clouds barely form, except at higher latitudes. For this planet, the visual albedo is 58% and the bond albedo (ability to reflect all radiation) is 53%. This planet appears greenish at lower latitudes and more yellow at higher latitudes. The colors are due to sulfur clouds.

Zeta Reticuli Bb[]

Zeta Reticuli Bb is a small, airless planet about the size of our Moon. It orbits at the similar distance as Mercury orbits our Sun with its year lasting one-fifth of an Earth year. Its orbit is circular at e=0.025, compared to e=0.206 for Mercury. It is very dense, meaning it is made mainly of heavy metals. It has a thick crust, splitting into layers of silicate rocks, lead, mercury, and gold from top to bottom. Its mantle is thin but has a big core about 60% the total size of the planet.

The planet takes 4556 days to rotate once on its axis at a velocity of just 112 times faster than average human walking speed. Its gravitational pull is over 123 times stronger than Mercury despite its similar mass due to its very high density. The surface temperature is about the same as Mercury's and is pockmarked with craters.

Zeta Reticuli Bc[]

Zeta Reticuli Bc is an ocean planet with the orbital period of 35 of a year. It has a diameter of 15.5 Mm (2.4 Earths) and surface area of about 3000 Mm2, six times that of Earth's. The planet contains 6.6 times more matter than Earth contains and orbit at 0.705 AU.

The global ocean is made mainly of water and is 1300 km deep. Its atmosphere is made of water vapor, nitrogen, with small amounts of hydrogen and helium. Its temperature is 217°F, just above the boiling point of water, but pressure at the ocean's surface under a layer of thick atmosphere allow water to exist as a liquid.

Zeta Reticuli Bd[]

Zeta Reticuli Bd is a super-Earth orbiting at Mars-like distance from the star. The planet masses 4.15 M, which is 39 times more massive than Mars. It is 1.42 times the size of Earth and is very dense, two times denser than Mars. It is a barren world with the surface temperature of 200°F.

Zeta Reticuli Be[]

Zeta Reticuli Be is a mid-Earth, 88% the mass of Earth and 86% the size. This planet appears almost totally white with a visual albedo of 99.5%, due to the surface covered in thick layers of ice, because the surface temperature is −132°F. The planet has a thin atmosphere made of carbon dioxide, carbon monoxide, methane, nitrogen, and water vapor.

This planet orbits at a semimajor axis of 4.21 AU (629 Gm) in a 8.69-year period. The planet takes 2717 hours to complete its rotation. Strength of gravity is 20% greater than Earth's.

Zeta Reticuli Bf[]

Zeta Reticuli Bf is the outermost planet of the secondary star's planetary system. It orbits at 6.63 AU (992 Gm) for a planet containing same amount of matter as Mars have. It takes 17.2 years to orbit once around the star with a very high eccentricity of 0.638, meaning the distance varies from 2.40 AU (359 Gm) to 10.86 AU (1624 Gm).

The planet's diameter is 7.126 megameters (4428 miles), which is about the size of Mars. This makes gravity just 13 as strong as on Earth and density 60% that of Earth's or about the same as that of the Moon. It's rotation takes 7.8 days or more than 187 hours to complete one spin. It has a very high axial tilt, at 61.4°.

Its surface temperature is about the same as on Saturn's moon Titan, resulting that the planet looks similar to Titan. The planet's surface contains lakes and seas of liquid methane and other hydrocarbons, surrounded by the atmosphere made mainly of nitrogen, carbon monoxide, methane, and hydrocarbons. Its atmospheric pressure is five times greater than Earth's and 312 times greater than Titan's.