Quick(ish) Sci-Fi System Generation

The following is a quick(ish) system to generate planets orbiting a star for a sci-fi game.
It's also useful for compulsive completists (like me) who want to know what the home-system of various Saucer-Men looks like.
There's been a whole lot of discoveries and science involving exoplanets the past decade or so and some of that is incorporated here on this chart.  Some of my definitions come from The Planetary Habitability Laboratory of the University of Puerto Rico at Arecibo webstie.

Some Definitions:

Dwarf Planet, barely a planet at all.

Mercurian, under 0.1 Earth Masses

SubTerran, 0.1 to 0.5 Earth Masses

Terran, 0.5 to 2.0 Earth Masses

SuperTerran, 2-10 Earth Masses

Neptunian, 10-50 Earth Masses

Jovian,50-200 earth masses.

SuperJovian, over 200 Earth Masses up to 80 times the mass of Jupiter.

They can be Hot (typically near their star but some jovians produce their own energy), Warm (habitable zone) and Cold (outer zone)

Habitable worlds (and moons) are defined by a mean thermo-class with ranges that could support life we'd be compatible with (or recognize) on some level: Hyperthermo  100 C to 150 C, Thermo 50 C to 100 C, Meso 0 C to 50 C, Psychro -50 C to 0 C, and Hyposychro -100 C to -50 C. 

The chance for a world to be populated depends on the sci-fi universe. For soft Space Opera or Saucer-Men universe I'd say any of the 5 picky Thermo classes for a habitable world means the world has a 90% or higher chance of having life, a warm world should have a 33% chance in such a universe and all other shoudl have a 2% chance (Space Opera worlds are strange). For a trek-o-verse any of the terran worlds has a 99% chance of having life, all others should be about 5%. For a "hard" sci-fi universe terran worlds with the 5 thermo-class zones should have a 30% chance of life, other Terran, SubTerran and SuperTerran worlds shoudl likely be 3% (or less), and others are probably lifeless unless the GM thinks that would be no fun.

Number of Planets

How many planets in a system?  In real-life it seems to depend on star size but research is showing us previous schemes of classification are  not holding up to reality. So I’m going to go abstract and simple here.

Each star has three zones: Inner, Mid, and Outer. Inner planets will tend to be Hot, Outer ones will tend to be cold.

In this generation method each star has 1d8 inner zone worlds, 1d6 Mid zone worlds, and 2d6-2 outer Zone worlds.

Inner Zone World Table

1-2 Hot Dwarf

3-15 Hot Mercurian

16-25 Hot SubTerran

26-34 Hot Terran, 1d6-4 Moons

35 Hyperthermo-Terran, 1d6-4 Moons

36-45 Hot SuperTerran, 1d6-3 Moons

46-60 Hot Neptunian, 1d6-3 Moons

61-90 Hot Jovian, 1d6-4 Moons

91-100 Hot SuperJovian, 1d6-4 Moons

Mid “Habitable”-Zone World Table

1-2 Asteroids

3-4 Warm Dwarf, 1d6-4 Moons

5-10 Warm Mercurian, 1d6-4 Moons

11-16 Warm SubTerran, 1d6-4 Moons

17-19 HyperthermoSubTerran,1d6-4 Moons

20-21 ThermoSubTerran, 1d6-4 Moons

22 MesoSubTerran,  1d6-4 Moons

23-25 Hot Terran, ,  1d6-4 Moons

26-29 HyperthermoTerran,  1d6-3 Moons

30-33 ThermoTerran,  1d6-3 Moons

34- 38 MesoTerran, 1d6-3 Moons

39- 40 PsychroTerran , 1d6-3 Moons

41 HypoPsychroTerran ,  1d6-3 Moons

42 Warm SuperTerran,  1d6-2 Moons

43-44 HyperthermoSuperTerran, 1d6-2 Moons

45-47 ThermoSuperTerran, 1d6-2 Moons

48-50 MesoSuperTerran, 1d6-2 Moons

51-52 PsychroSuperTerran, 1d6-2 Moons

53 HypoPsychroSuperTerran, 1d6-2 Moons

54-60 Warm Neptunian, 1d6 Moons

61-65 Hot Jovian, 1d10 Moons

66-80 Warm Jovian, 1d10 Moons

81-85 Hot Superjovian, 1d6

86-100 Warm SuperJovian,1d6

Outer-Zone World Table

1-3 Asteroids

4-10 Cold SubDwarf, 1d6-4 Moons

11-15 Cold Dwarf, 1d6-4 Moons

16-20 Cold Mercurian, 1d6-3 Moons

21-24 Cold Subterran, 1d6-2

25 HypoPsychroSubTerran, 1d6-4 Moons

26-29 Cold Terran, 1d6-3 Moons

30 HypoPsychroTerran, 1d6-4 Moons

31-34 Cold SuperTerran, 1d6-1 Moons

35 PyshcroSuperTerran, 1d6-2 Moons

36 HypoPsychroSuperTerran, 1d6-3 Moons

37-75 Cold Neptunian, 1d12-1 Moons

76 Warm Jovian, 2d12 Moons

77-90 Cold Jovian, 3d12 Moons

91 Hot SuperJovian, 1d8Moons

92 Warm SuperJovian, 1d8 Moons

93-100 Cold SuperJovian, 1d8 Moons

Moon sizes for SubTerran and Smaller Worlds(1d10)

1-3 Planetesimal

4-9 SubDwarf

10 Dwarf

Moon sizes for Terran and SuperTerran Worlds (1d20)

1-3 Planetesimal

4-10 SubDwarf

11-17 Dwarf

18-19 Mercurian

20 Ring

Moon Sizes for Neptunian and Larger Worlds (1d100)

1-15 Planetesimal

16-40 SubDwarf

41-70 Dwarf

71-80 Mercurian

81-83  Terran

84-99 Ring

100 SuperTerran

Moons can be same size class as a world but not larger.

Moons will typically be same temperature class as appropriate for zone.

In Mid Zone there is a 10% chance a moon of a super-terran or larger world will have an atmosphere allowing for Thermic variance if mercurian or larger.

1-9 HyperthermoMoon

10-20  ThermoMoon

21-40  MesoThermicMoon

41-70 PsychroMoon

71-100 HypoPsychroMoon

In the Outer Zones there is a 10% chance of a moon of a super-terran or larger world with Thermic variance if dwarf sized or larger.

1 HyperThermoMoon

2-4 Thermo Moon

5-8 MesoThermicMoon

9-20 PsychroMoon

21-100 HypoPsychroMoon

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There you go a basic system to generate a system for a sci-fi game universe.

 I have an old pickier then Traveller world generation system compatible with Traveller I'm considering renovating after recent reading about what scientists have found and think could be out there, exo-planet theory and exploration is an amazing and growing field.