Shuriken Galaxy - NeoKosmos Planet Finder Mission (Omnigeek6's systems)

[Omnigeek6]

The Shuriken Galaxy is a dwarf spiral galaxy approximately 9800 ly in diameter, with an average disk thickness of 150 ly, and a bulge thickness of 420 ly. It is rich in gas and dust; although it has a mass of about 600 million suns, half of this mass is dark matter, and over 90% of the remaining mass is gas and dust, the remaining matter being found in nearly 50 million stars, with an average mass slightly above 0.5 suns. It is classified as a Dwarf SAb galaxy, or a kS2 under the Yerkes scheme. It has five well-defined spiral arms, labeled Alpha through Epsilon.

The NeoKosmos Planet Finder Mission uses a fleet of three 500 meter wide-spectrum space telescopes located in a polar orbit around a star in the Shuriken Galaxy's halo to conduct radial velocity and direct observations of planets. Wormhole probes are also set up to specific stars.

The following is a series of summaries of systems which have been studied by dedicated missions.

[Omnigeek6]

((Sorry for the double post. My idea is to have one post for each system.))

We start with NK004 Amaterasu, the best studied system. Given the striking similarity one of the planets bears to Earth, there is a constant robotic presence in the system, including long-term surface and atmospheric probes.

NK004 (Amaterasu):
Arm: Delta
Galactic orbital radius: 3600 ly
Mass: 0.84 suns
Radius: 6.55X10^5 km
Surface temperature: 5570 K
Spectral class: G7V
Luminosity: 0.5 suns
Age: 3.4 Gy.

Ninigi:
Average orbital distance: .12 AU
Eccentricity: .43
Inclination: 25.4 degrees
Radius: 44230 km
Density: 0.7 g/cm^3
Mass: 41.7 earths
Surface Gravity: .87 Gs.
Sidereal rotation: Tidally locked.
Axis tilt: 25.4 degrees
Atmosphere: Contains large amounts of methane, carbon monoxide, and alkali metals.
Other: Ninigi may be a blue marble, but it’s not much like earth. Its eccentric orbit gives it a periastron of 1/16th of an AU and an apastron of 1/6th of an AU, and temperatures varying from 700 to 1400 degrees Fahrenheit, far too hot for water. Its mass is between that of Neptune and Saturn, with its high temperature giving it densities comparable to the latter, although its diameter varies within its 16.6 earth day long year. Its atmosphere varies from a methane based deep blue at apastron to green-tinged purple at periastron, the latter caused by carbon monoxide and alkali metals in its clouds. It is, on average, Amaterasu’s closest planet, a title wrested only for short periods less than once per century as Fujin’s highly eccentric orbit takes it through a stargrazing periastron. Ninigi has only one large moon, with a few tiny shepherd moons buried within the dust of the planet’s ring.
   Moons: Konohanasakuya: Distance: 137916 km, ecc: .24, inc: -13.5 degrees, mass: 1.62 moons, diameter: 3631 km
Photo: http://s844.photobucket.com/albums/ab6/Omnigeek6/Universe%20Sandbox%20Creations/?action=view&current=Ninigi.png

Uzume:
Average Orbital Distance: .39 AU
Eccentricity: .082
Inclination: 9.08 degrees
Radius: 2788 km
Density: 5.04 g/cm^3
Mass: .076 earths
Surface Gravity: 0.4 Gs.
Sidereal rotation: 174 hours, 30 minutes, 12 seconds
Axis tilt: 0.24 degrees
Atmosphere: thin CO2 and water vapor atmosphere.
Other: Similar to Mars, Uzume is a small, rocky world, comparable to Mars, orbited by two captured asteroids. However, it is far hotter, orbiting at around the distance of mercury, although around a cooler star. Surface temperatures range from over 450 degrees Fahrenheit on the day side to -200 on the night side, due to its slow rotation and low heat transfer through its thin atmosphere. As such, it there is a continuous snow line at sunset, and evaporation line at sunrise, and the planet’s night side is frosted with water ice. The day side contains some liquid water at high latitudes. However, no life is known to exist there, due to repeated freezing cycles. Uzume has a basaltic crust, and although it is much less geologically active on earth, there are occasional isolated lava flows inside deep craters, gradually filling them in.
   Moons: Uzume-A: Distance: 20765 km, ecc: .26, inc: 9 degrees, mass: 4.9 X 10^17 kg, diameter: 65 km
      Uzume-B: Distance: 53400 km, ecc: .52, inc: 40 degrees, mass: 2.3 X 10^18 kg, diameter: 108 km
Photo: http://s844.photobucket.com/albums/ab6/Omnigeek6/Universe%20Sandbox%20Creations/?action=view&current=UzumeseenfromUzume-A.png
Inari:
Average Orbital Distance: .75 AU
Eccentricity: 0.017
Inclination: 5 degrees
Radius: 4800 km
Density: 5.25 g/cm^3
Mass: .41 earths
Surface Gravity: .75 Gs.
Sidereal Rotation: 34 hours, 15 minutes, 47 seconds.
Axis tilt: 29.8 degrees.
Atmosphere: 72% N2, 25% O2, 3% other gases.
Other: Inari is basically an earth analog. However, it has lighter gravity, a longer day, and other mentioned features.
   Moons: Inari-A: distance: 27000 km, ecc: .19, inc: 3.4 degrees, mass: .04 moons, diameter: 1188 km
      Inari-B: distance: 57000 km, ecc: .13, inc: 1.7 degrees, mass: .23 moons, diameter: 2076 km
      Inari-C: distance: 117000 km, ecc: .32, inc: -2.5 degrees, mass: .07 moons, diameter: 1452 km
      Inari-D: distance: 220000 km, ecc: .24, inc: 5.3 degrees, mass: .06 moons, diameter: 1357 km
      Note: Because Inari’s moons have relatively high masses, exact orbital characteristics fluctuate somewhat from the listed values. Also note that the night sky on this planet is truly spectacular: at apsis, Inari-D appears about half the size of the moon, Inari-C looks the same size, and Inari-B and Inari-A appear to be 3.5 and 4.5 times the size of our own moon! Combined, the moons’ add up to 0.4 moon masses, slightly less than Earth’s moon in relation to their parent, but because they orbit much closer to Inari, especially A and B, the planet experiences powerful, chaotic tides. A and B can both create total stellar eclipses, and C can create an annular eclipse. In addition, Inari-A has an orbital period shorter than Inari’s day, while those of the planet’s other moons are longer. As such, it appears to move the opposite direction in the sky.
Photo: http://s844.photobucket.com/albums/ab6/Omnigeek6/Universe%20Sandbox%20Creations/?action=view&current=Inariandmoons.png

More information on Inari coming soon.

Ryujin:
Average Orbital Distance: 1.86 AU
Eccentricity: .058
Inclination: 7.1 degrees
Radius: 12600 km
Density: 4.62 g/cm^3
Mass: 6.48 earths
Surface Gravity: 1.66 Gs.
Sidereal Rotation: 19 hours, 27 minutes, 49 seconds.
Axis tilt: 23.4 degrees
Atmosphere: 48% N2, 21% H2, 10% He, 8% NH3, 5% CH4, 4% CO2, 1% H2O, 3% other gases.
Other: Ryujin is a “super-earth,” a terrestrial planet significantly larger than our own. Because of its strong gravity and great distance from Amaterasu, this planet has accumulated a thick atmosphere, with surface pressures nearly ten times those on Earth. Often compared to “a frozen Venus” its surface is partially obscured by thick clouds of water ice, with some ammonia and carbon dioxide. The large amount of methane in the atmosphere produces a strong greenhouse effect, which, combined with high atmospheric pressures, allows the latter two of these substances to form lakes, rivers, and oceans on its surface, much like on Titan. In addition, the crust contains large amounts of water ice. Ryujin also sustains active plate tectonics, and has many active volcanoes, spewing large amounts of water vapor, carbon dioxide, and ammonia into the atmosphere, as well as partially melting the crust and causing icebergs large and small to float away into the oceans. Unlike icebergs on earth, these only ever melt when currents carry them into another warm area. Ryujin’s moons are mostly asteroids and small planets, captured shortly after its formation.

Photo: http://s844.photobucket.com/albums/ab6/Omnigeek6/Universe%20Sandbox%20Creations/?action=view&current=Inariandmoons.png

Rajin:
Average Orbital Distance: 6.29 AU
Eccentricity: 0.036
Inclination: 9.19 degrees
Radius: 77808 km
Density: 1.65 g/cm^3
Mass: 1.7 jupiters
Surface Gravity: 3.65 Gs.
Sidereal Rotation: 8.45 hours
Axis tilt: 7.5 degrees
Atmosphere: 88% H2, 10% He, 2% other gases.
Other: Rajin is the largest planet in the Amaterasu system apart from Amatsu, but the latter is located in the Oort Cloud, and his little to no gravitation influence on the rest of system. Rajin is heavier than Jupiter, but otherwise very similar, with a hydrogen and helium atmosphere, and clouds of ammonia and water ice. High windspeeds and large storm systems are common, though these storms rarely, if ever last longer than 20 years. Rajin’s ring system consists of the A ring at 2.0-1.6 radii, and the thinner B ring at 1.5-1.1 radii.
   Moons: Rajin-A: This tiny moon is less than 500 miles in diameter, with a total land area only as large as the country of Mexico. Its closest analog in our solar system is Io, but Rajin-A orbits a larger planet at only half the distance, and is even more geologically active. Distance: 204537 km, ecc: 0.026, inc: 4.24.  Diameter 778 km, mass 0.012 moons
      Rajin-B: Like Rajin-A, this moon experiences powerful tidal forces. The resulting heat has melted its core and given it a strong magnetic field, aided by the fact that at 1.46 lunar masses, it is second only to Rajin-E. However, this field is overpowered by that of Rajin. Because it is considerably hotter than Jupiter’s moons, its icy surface has melted into a patchwork of lakes, pockmarked by cryovolcanoes which propel water vapor and other gases into its sky, forming a thin atmosphere, with wispy clouds. Rajin-C, Rajin-D, and Rajin-E have subsurface oceans, but Rajin-B is the only moon in the Amaterasu system to have liquid water on its surface, comprising half its surface area, or 1/4th the area of the Atlantic Ocean, but often much deeper. As can be expected, Rajin-B contains life, including both unicellular and colonial chemoautotrophs and radioautotrophs, as well as chemoheterotrophs or saprotrophs, and a very small number of radioheterotrophs. These organisms consist of cells without organelles, but most have differentiated nuclei. However, since Amaterasu is only 3 billion years into its 15 billion year lifespan, more complex life may yet evolve. Distance: 267751 km, ecc: 0.024, inc: 4.23. Diameter 4315 km, mass 1.46 moons
      Rajin-C to Rajin-E: These moons, of varying sizes, all are icy worlds, with subterranean oceans. Unicellular life is probable. Distance: 351223, 646338, 1631504 km. Diameters 3856, 2847, 5672 km. Masses 1.22, 0.45, and 3.02 moons.
      Rajin-F: The smallest notable moon of Rajin, this is a relatively large shepherd moon which sweeps out the divide between Rajin’s A and B rings. Rajin’s other moons are captured asteroids, typically farther out than Rajin-E.

Photo: http://s844.photobucket.com/albums/ab6/Omnigeek6/Universe%20Sandbox%20Creations/?action=view&current=Rajinandmoons.png

Omoikane:
Average orbital distance: 13.1 AU
Eccentricity: .07
Inclination: 12.7 degrees
Radius: 71727 km
Density: 1.00 g/cm^3
Mass: .81 jupiters
Surface Gravity: 2.04 Gs.
Sidereal Rotation: 14.27 hours
Axis tilt: 25.6 degrees
Atmosphere: 92% H2, 7% He, 1% other gases.
Other: Omoikane’s distance from Amaterasu is between those of Saturn and Uranus in our own solar system, but the space around it is colder than either. However, at a Jupiter-like size, Omoikane generates a large amount of heat, and is relatively warm.
   Moons: Because of its large ring system, Omoikane is often compared to Saturn. However, the total mass of objects orbiting Omoikane is more than 50% greater than the mass of Saturn’s rings and moons, and its main ring system extends farther. Omoikane also has a whopping 12 major moons, all of which are at least somewhat larger than Saturn’s moon Mimas. Omoikane-A actually orbits within the rings, and as a consequence is the most heavily cratered body in the Amaterasu system, due to bombardment by ring particles, mostly before it swept out the main gap in the ring system. Omoikane-B is responsible for defining the outer edge of the rings via an unstable 7:6 resonance. In addition, its surface is dotted with cryovolcanoes, and flows of ammonia-water “lava” have at least partially filled many of its craters, smoothing its surface. Omoikane-C is as large as earth’s moon, although lighter. Its most distinct surface feature is an impact crater as large as the state of Texas, surrounded by massive fractures several miles deep, and mountains opposite it. Similar, but smaller craters are accompanied by the same types of feature. Omoikane-D  is the largest of the family, 1.64 times as heavy as Earth’s moon and larger than Mercury. It can be compared to Titan. However, Omoikane-D is much colder, and on its surface methane and other hydrocarbons freeze, while oxygen condenses to liquid and substances like nitrogen and carbon monoxide are just barely gaseous, forming an atmosphere about half the density of earth’s. Omoikane-E, which orbits at D’s L4 point, is itself 700 km in diameter. B and F also have Trojan companions, but they are only a few kilometers in diameter. G and H are in a 4:3 resonance, with the former in a highly eccentric orbit and both at comparatively high inclinations. More surprising still, Omoikane-H even has its own small moon. I and J share a “horseshoe orbit.” On the outer edge of the system, K leisurely progresses through an orbit almost as long as Inari’s year. Finally, Omoikane L plummets towards its parent in a highly inclined, retrograde orbit.

Photo: http://s844.photobucket.com/albums/ab6/Omnigeek6/Universe%20Sandbox%20Creations/?action=view&current=Omoikaneandrings.png

Hachiman:
Average orbital distance: 24.8 AU
Eccentricity: .24
Inclination: 16.7 degrees
Radius: 3590 km
Density: 2.24 g/cm^3
Mass: .073 earths
Surface Gravity: .23 Gs.
Sidereal Rotation: 11.2 hours
Axis tilt: 14.3 degrees
Atmosphere: Trace hydrogen, helium, and at periastron nitrogen.
Other: Hachiman’s surface is a tholin-induced red, so it should not some as a surprise the small world is named after a war god. Although dwarfed by its neighbors, Omoikane and Fukurokuju, at the diameter of Mars and the mass of Uzume, it is large for an ice ball. It orbits in a 3:2 resonance with Fukurokuju, and is orbited by five captured icy objects, similar to our solar system’s KBOs.

Fukurokuju:
Average orbital distance: 32.7 AU
Eccentricity: .21
Inclination: 10.7 degrees
Radius: 39937 km
Density: 1.5 g/cm^3
Mass: 67 earths
Surface Gravity: 1.71 Gs.
Sidereal Rotation: 13.37 hours.
Axis tilt: 39.7 degrees
Atmosphere: Hydrogen and helium, with some methane and tholins. (Color R=200, G=100, B=150)
Other: Fukurokuju is Amaterasu’s only ice giant, and even so its mass is closer to Saturn that Neptune. However, its composition is decidedly Neptunian, with its dense atmosphere colored a vivid purple by a combination of methane and tholins. The planet’s thin ring was most likely formed when a small moon got too close, and was torn apart by tidal forces. Fukurokuju’s major moons were all most likely formed from accretion. However, they are tiny compared to those of the system’s other giant planets, with none more massive than Earth’s moon, and there are only four. Fukurokuju also has a large family of captured comet-like objects similar to KBOs.
Fukurokuju-A: Distance: 103625 km, Eccentricity: 0.006, Inclination: 0.37 degrees, diameter: 1216 km, mass: 0.016 moons.
Fukurokuju-B: Distance:173963 km, Eccentricity: 0.02, Inclination: -0.2 degrees, diameter: 2915 km, mass: 0.27 moons.
Fukurokuju-C: Distance: 276051 km, Eccentricity: 0.003, Inclination: 0.1 degrees, diameter: 684 km, mass: 1.91X10^20 kg.
Fukurokuju-D: Distance: 525829 km, Eccentricity: 0.0077, Inclination: 0.36 degrees, diameter: 1399 km, mass: 0.024 moons.

Photo: http://s844.photobucket.com/albums/ab6/Omnigeek6/Universe%20Sandbox%20Creations/?action=view&current=Fujurokuju.png

Beyond Fukurokuju: Several sets of distant objects orbit Amaterasu; 2:3 resonants, 3:4 resonants, 3:5 resonance, 3:7 resonances, 1:2 resonants, and 2:5 resonants are most common. However, distant resonances up to 1:4 occur.

The largest planets lying in each resonance are shown, along with a couple of other bodies.

Susanoo (2:3 resonant): The 2:3 Fukurokuju resonants are the Amaterasu system’s equivalent of Plutinos. As such, the first to be discovered was named for a principle Shinto god of the underworld. However, Susanoo turns out to dwarf Pluto, and is the 5th largest TFO.

Yuki (3:4 resonant): Yuki is tiny, the smallest planet in the Amaterasu system and barely large enough to qualify at all, with an orbit huddling close to that of its giant sibling. However, its albedo is incredibly bright, earning it the name of a goddess of snow and winter; fitting for a world so cold the very air freezes out of the sky. This planet is so small, it can’t even muster a gravitational pull 1% that of earth.

Shoki (3:5 resonant):

Koshin (4:7 resonant):

Amida (2:5 resonant):

Okuni (1:4 resonant):