DETERMINE STAR

Roll on the Stellar Class and Mass Table to Determine the class and mass of the system’s primary star. Roll 5D6 to determine the Stellar Class OBAFGKM, and then roll 5D6 to determine the Class Grade. Check the Luminosity in the Stellar Luminosity Table.

Stellar Class and Mass Table

	5D6	≥30	29-28	27-26	25-24	23-22	21-20	≤19
	O	B	A	F	G	K	M
5D6		blue	blue white	white	yellow white	yellow	light orange	orange red
5-17	9	27.20 M☉	3.49 M☉	1.47 M☉	1.08 M☉	0.82 M☉	0.49 M☉	0.12 M☉
18-20	8	38.40 M☉	4.88 M☉	1.54 M☉	1.11 M☉	0.85 M☉	0.52 M☉	0.15 M☉
21-22	7	49.60 M☉	6.27 M☉	1.61 M☉	1.15 M☉	0.87 M☉	0.56 M☉	0.19 M☉
23-24	6	60.80 M☉	7.66 M☉	1.68 M☉	1.18 M☉	0.90 M☉	0.59 M☉	0.23 M☉
25	5	72.00 M☉	9.05 M☉	1.75 M☉	1.22 M☉	0.92 M☉	0.63 M☉	0.27 M☉
26	4	83.20 M☉	10.44 M☉	1.82 M☉	1.26 M☉	0.94 M☉	0.66 M☉	0.30 M☉
27	3	94.40 M☉	11.83 M☉	1.89 M☉	1.29 M☉	0.97 M☉	0.70 M☉	0.34 M☉
28	2	105.60 M☉	13.22 M☉	1.96 M☉	1.33 M☉	0.99 M☉	0.73 M☉	0.38 M☉
29	1	116.80 M☉	14.61 M☉	2.03 M☉	1.36 M☉	1.02 M☉	0.77 M☉	0.41 M☉
30	0	128.00 M☉	16.00 M☉	2.10 M☉	1.40 M☉	1.04 M☉	0.80 M☉	0.45 M☉

M☉ Solar Mass. (Stars larger than 128 M☉ are quite rare)

The resulting star has Mass and Luminosity based on its Stellar Class and its Class Grade as per the Stellar Class and Mass Table above and the Stellar Luminosity Table below.

Stellar Luminosity Table

	O	B	A	F	G	K	M
Grade	blue	blue white	white	yellow white	yellow	light orange	orange red
9	30,000 L☉	25.00 L☉	5.00 L☉	1.50 L☉	0.60 L☉	0.08 L☉	0.01 L☉
8	50,934 L☉	50.80 L☉	8.60 L☉	2.13 L☉	0.76 L☉	0.17 L☉	0.02 L☉
7	86,475 L☉	103.21 L☉	10.40 L☉	2.45 L☉	0.84 L☉	0.22 L☉	0.03 L☉
6	146,817 L☉	209.69 L☉	12.20 L☉	2.76 L☉	0.92 L☉	0.27 L☉	0.03 L☉
5	249,266 L☉	426.06 L☉	14.00 L☉	3.08 L☉	1.01 L☉	0.31 L☉	0.04 L☉
4	423,202 L☉	865.66 L☉	15.80 L☉	3.39 L☉	1.09 L☉	0.36 L☉	0.05 L☉
3	718,510 L☉	1,758.86 L☉	17.60 L☉	3.71 L☉	1.17 L☉	0.41 L☉	0.05 L☉
2	1,219,884 L☉	3,573.66 L☉	19.40 L☉	4.02 L☉	1.25 L☉	0.45 L☉	0.06 L☉
1	2,071,113 L☉	7,260.98 L☉	21.20 L☉	4.34 L☉	1.33 L☉	0.50 L☉	0.07 L☉
0	3,516,325 L☉	14,752.90 L☉	23.00 L☉	4.65 L☉	1.41 L☉	0.55 L☉	0.07 L☉

L☉ Sol Sun Equivalents of Luminosity.

Roll on the Companion Star Table to determine if a solar system’s central star has a Companion Star. A result equal to or greater than the Target Number means that there is a Companion Star. If the result is 12, not only is there a companion star, but the roll is made again to determine if there is one more star after that. The same rule applies; meaning a system with more than 3 stars is possible, in the unlikely instance the rolls keep having a result of 12.

Companion Star Table

	O	B	A	F	G	K	M
Grade	blue	blue white	white	yellow white	yellow	light orange	orange red
2D6	4+	5+	6+	7+	8+	9+	10+

To determine the Stellar Classification of the companion star, roll on the Stellar Class and Mass table and the Stellar Luminosity table. If the result would give the star a Class that is larger than the Class of the primary star, assign it one Class smaller than the primary star instead (with O being the largest class and M being the smallest). If the Grade number is lower (lower grade means higher Luminance and Solar Mass) than the Grade number of the primary star, assign it one Grade higher than the primary star instead. Do this for each additional star ensuring that the next star always has a Class equal to or smaller than the previous one and a Luminance equal to or lower than the previous one in the same way.

To avoid confusion, the name of a star will sometimes be written in a specific format starting with the UIA (Union astronomique internationale / International Astronomic Union) name or other popular name if it has one (with a letter indicating its place in a binary or multi-star system if this applies), followed by the Harvard Stellar Class (O,B,A,F,G,K or M) or a designation based on its Association cluster (OB2#12 for example), then its Grade (0 to 9), then its Yerkes Luminosity Grade (0 or Ia+, Ia, Iab, Ib, II, III, IV, V, sd (prefix) or VI, c) as noted below. It should be noted that higher grade numbers mean stars of lower luminosity.

Roll Companion Star Orbit.

To determine the distance of a Companion star from the star that it orbits, roll 3D6 and assign a distance according to the Orbit Table Below along the column of the Stellar class of the star that it orbits.

If you are not concerned about the specifics of the generated solar system and only wish to generate its Main World, skip to “Determine Main World” below.

If you need an exact distance for the companion star but don’t want to arbitrarily decide this, place it on the lower value of a range. For a roll of 3-4, the lower value is 0. When stars share the same range, place them evenly spaced in and between the higher and lower values of the range.

For multi-star systems, the first companion star orbits the Primary star and then a D6 roll is made in order to determine which star the succeeding stars orbit. On a 1-3 the companion star orbits the same star that the last one did. On a 4 to 6 the companion star orbits the previously generated companion star.

If you later find a companion star’s radius to be equal to or larger than the assigned distance, consider it to be a contact star (contact stars are stars distinctly separate from one another but close enough to touch and share gaseous envelopes).

Orbit Table

	Distances in AU per Stellar Class of Primary Star (Roll 3D6)
Result	O	B	A	F	G	K	M
3-4	<50	<10	<5	<1	<0.5	<0.25	<0.125
5-7	50 to <100	10 to <50	5 to <10	1 to <5	0.5 to <1	0.25 to <0.5	0.125 to <0.25
8-11	100 to <500	50 to <100	10 to <50	5 to <10	1 to <5	0.5 to <1	0.25 to <0.5
12-14	500 to <1000	100 to <500	50 to <100	10 to <50	5 to <10	1 to <5	0.5 to <1
15-16	5000 to <10000	500 to <1000	100 to <500	50 to <100	10 to <50	5 to <10	1 to <5
17	10000 to <50000	5000 to <10000	500 to <1000	100 to <500	50 to <100	10 to <50	5 to <10

On a roll of 18, roll again but multiply the resulting value by 10.

DETERMINE ZONES AND LIMITS

Determine zones and limits by taking the Square Root of Solar Luminance of the Primary Star and multiplying it to get the Limit. Between two limits are a Zone. Zones and Limits determine the Position worlds within a Solar System. This is influenced by the Solar Radiation that can push lighter and more volatile elements farther out, despite the gravity of the star.

Zone Formula Table

Zone	Measurements
Infernal Zone	0 to <√L☉ 0.4AU
Hot Zone	Optimistic Habitable Zone	√L☉ 0.4AU to <L☉ 0.8AU
Conservative Habitable Zone	Optimistic Habitable Zone	√L☉ 0.8AU to <L☉ 1.2AU
Cold Zone	Optimistic Habitable Zone	√L☉ 1.2AU to <L☉ 4.85AU
Outer Solar System	√L☉ 4.85AU or more

Zone Enumerated Table

Luminosity	Infernal Zone	Hot Zone	Conservative Habitable Zone	Cold Zone	Outer Solar System
0.01 L☉	0 to 0.04 AU	0.04 AU to 0.08 AU	0.08 AU to 0.12 AU	0.12 AU to 0.49 AU	0.49 AU and above
0.02 L☉	0 to 0.06 AU	0.06 AU to 0.11 AU	0.11 AU to 0.17 AU	0.17 AU to 0.69 AU	0.69 AU and above
0.03 L☉	0 to 0.07 AU	0.07 AU to 0.14 AU	0.14 AU to 0.21 AU	0.21 AU to 0.84 AU	0.84 AU and above
0.04 L☉	0 to 0.08 AU	0.08 AU to 0.16 AU	0.16 AU to 0.24 AU	0.24 AU to 0.97 AU	0.97 AU and above
0.05 L☉	0 to 0.09 AU	0.09 AU to 0.18 AU	0.18 AU to 0.27 AU	0.27 AU to 1.08 AU	1.08 AU and above
0.06 L☉	0 to 0.10 AU	0.10 AU to 0.20 AU	0.20 AU to 0.29 AU	0.29 AU to 1.19 AU	1.19 AU and above
0.07 L☉	0 to 0.11 AU	0.11 AU to 0.21 AU	0.21 AU to 0.32 AU	0.32 AU to 1.28 AU	1.28 AU and above
0.08 L☉	0 to 0.11 AU	0.11 AU to 0.23 AU	0.23 AU to 0.34 AU	0.34 AU to 1.37 AU	1.37 AU and above
0.17 L☉	0 to 0.16 AU	0.16 AU to 0.33 AU	0.33 AU to 0.49 AU	0.49 AU to 2.00 AU	2.00 AU and above
0.22 L☉	0 to 0.19 AU	0.19 AU to 0.38 AU	0.38 AU to 0.56 AU	0.56 AU to 2.27 AU	2.27 AU and above
0.27 L☉	0 to 0.21 AU	0.21 AU to 0.42 AU	0.42 AU to 0.62 AU	0.62 AU to 2.52 AU	2.52 AU and above
0.31 L☉	0 to 0.22 AU	0.22 AU to 0.45 AU	0.45 AU to 0.67 AU	0.67 AU to 2.70 AU	2.70 AU and above
0.36 L☉	0 to 0.24 AU	0.24 AU to 0.48 AU	0.48 AU to 0.72 AU	0.72 AU to 2.91 AU	2.91 AU and above
0.41 L☉	0 to 0.26 AU	0.26 AU to 0.51 AU	0.51 AU to 0.77 AU	0.77 AU to 3.11 AU	3.11 AU and above
0.45 L☉	0 to 0.27 AU	0.27 AU to 0.54 AU	0.54 AU to 0.80 AU	0.80 AU to 3.25 AU	3.25 AU and above
0.50 L☉	0 to 0.28 AU	0.28 AU to 0.57 AU	0.57 AU to 0.85 AU	0.85 AU to 3.43 AU	3.43 AU and above
0.55 L☉	0 to 0.30 AU	0.30 AU to 0.59 AU	0.59 AU to 0.89 AU	0.89 AU to 3.60 AU	3.60 AU and above
0.60 L☉	0 to 0.31 AU	0.31 AU to 0.62 AU	0.62 AU to 0.93 AU	0.93 AU to 3.76 AU	3.76 AU and above
0.76 L☉	0 to 0.35 AU	0.35 AU to 0.70 AU	0.70 AU to 1.05 AU	1.05 AU to 4.23 AU	4.23 AU and above
0.84 L☉	0 to 0.37 AU	0.37 AU to 0.73 AU	0.73 AU to 1.10 AU	1.10 AU to 4.45 AU	4.45 AU and above
0.92 L☉	0 to 0.38 AU	0.38 AU to 0.77 AU	0.77 AU to 1.15 AU	1.15 AU to 4.65 AU	4.65 AU and above
1.01 L☉	0 to 0.40 AU	0.40 AU to 0.80 AU	0.80 AU to 1.21 AU	1.21 AU to 4.87 AU	4.87 AU and above
1.09 L☉	0 to 0.42 AU	0.42 AU to 0.84 AU	0.84 AU to 1.25 AU	1.25 AU to 5.06 AU	5.06 AU and above
1.17 L☉	0 to 0.43 AU	0.43 AU to 0.87 AU	0.87 AU to 1.30 AU	1.30 AU to 5.25 AU	5.25 AU and above
1.25 L☉	0 to 0.45 AU	0.45 AU to 0.89 AU	0.89 AU to 1.34 AU	1.34 AU to 5.42 AU	5.42 AU and above
1.33 L☉	0 to 0.46 AU	0.46 AU to 0.92 AU	0.92 AU to 1.38 AU	1.38 AU to 5.59 AU	5.59 AU and above
1.41 L☉	0 to 0.47 AU	0.47 AU to 0.95 AU	0.95 AU to 1.42 AU	1.42 AU to 5.76 AU	5.76 AU and above
1.50 L☉	0 to 0.49 AU	0.49 AU to 0.98 AU	0.98 AU to 1.47 AU	1.47 AU to 5.94 AU	5.94 AU and above
2.13 L☉	0 to 0.58 AU	0.58 AU to 1.17 AU	1.17 AU to 1.75 AU	1.75 AU to 7.08 AU	7.08 AU and above
2.45 L☉	0 to 0.63 AU	0.63 AU to 1.25 AU	1.25 AU to 1.88 AU	1.88 AU to 7.59 AU	7.59 AU and above
2.76 L☉	0 to 0.66 AU	0.66 AU to 1.33 AU	1.33 AU to 1.99 AU	1.99 AU to 8.06 AU	8.06 AU and above
3.08 L☉	0 to 0.70 AU	0.70 AU to 1.40 AU	1.40 AU to 2.11 AU	2.11 AU to 8.51 AU	8.51 AU and above
3.39 L☉	0 to 0.74 AU	0.74 AU to 1.47 AU	1.47 AU to 2.21 AU	2.21 AU to 8.93 AU	8.93 AU and above
3.71 L☉	0 to 0.77 AU	0.77 AU to 1.54 AU	1.54 AU to 2.31 AU	2.31 AU to 9.34 AU	9.34 AU and above
4.02 L☉	0 to 0.80 AU	0.80 AU to 1.60 AU	1.60 AU to 2.41 AU	2.41 AU to 9.72 AU	9.72 AU and above
4.34 L☉	0 to 0.83 AU	0.83 AU to 1.67 AU	1.67 AU to 2.50 AU	2.50 AU to 10.10 AU	10.10 AU and above
4.65 L☉	0 to 0.86 AU	0.86 AU to 1.73 AU	1.73 AU to 2.59 AU	2.59 AU to 10.46 AU	10.46 AU and above

Example Zones Table

Zone	Worlds	Distance
Sun	-	0 AU
Infernal Zone	Mercury	0.4AU
Hot Zone (Optimistic Habitable Zone)	Venus	0.7AU
Conservative Habitable Zone	Earth	1AU
Cold Zone (Optimistic Habitable Zone)	Mars	1.5AU
Cold Zone (Optimistic Habitable Zone)	Asteroid Belt	2.8AU
Outer Solar System	Jupiter	5.2AU
Outer Solar System	Saturn	9.5AU
Outer Solar System	Uranus	19.8AU
Outer Solar System	Neptune	30AU
Outer Solar System	Pluto	39AU
Outer Solar System	Kuiper Belt	40AU

TECH LEVEL Table

This is only necessary when there is a great disparity in tech levels in the galactic area. Otherwise, the TL defaults to the setting Standard Tech Level (STL) or else, in case of some disparity, something closer to: rolling a result of 2 = STL -2; 3 to 4 = STL-1, 5 to 9 STL, 10 to 11 STL +1, 12 STL+2.

Roll 2D6 to determine the Tech level

2D6	TL	CE* TL	Equivalent
2	7	6.0	Early Space Age (1950-2000CE)
3	8	6.5	Commercial Space (2000-2050CE)
4	9	7.0	New Space Race (2050-2100CE)
5	10	7.5	Cis Lunar Development (2100-2200CE)
6-7	11	8.5	Interstellar Settlement and Mega Structures (2200-2300CE)
8	12	9.0	Post Earth Dependence. (2300-2400CE)
9	13	9.5	Early Jump-Drive (2400-2500)
10	14	10	Interstellar Space (2500-2600)
11	15	10.5	Interstellar Colonization
12	16	11	Self-Sufficient Mega Structures

Cepheus Engine

Using Cepheus Engine Tech Level instead of Mneme Tech Level.

Use the Mneme and Cepheus Engine Tech Level Reference Table to determine the equivalent TLs. The range of Tech Levels there are meant to allow different Campaigns set in different eras of human Spacefaring. The table goes into a bit more detail to show the great disparity between mere decades or centuries of technological development.

With regards to the seemingly arbitrary Human Era Dates, the written historical dates are not meant to represent any sort of expected pace of technological advancement so much as a simple note of when this occurred in our civilization for reference purposes. Civilizations are really unlikely to advance in their technologies at similar rates and obviously, all future dates are speculative and not based on real-life examples.

Mneme and Cepheus Engine Technology Level Reference Table

TL	Human Era (HE)	Age/Era	CE TL	CE descriptions & added descriptions
00	1 HE (10,000 BCE)	Neolithic Revolution	00.0	(Agriculture and organized society)
01	5,000 HE (5,000 BCE)	Bronze Age	01.0	Bronze Age
02	5,500 HE (500 BCE)	Axial Age	01.3	Iron Age
03	10,000 HE (0 CE)	Imperial Era	01.7	Medieval Era
04	11,500 HE (1500 CE)	Enlightenment	02.0	Renaissance
05	11,800 HE (1800 CE)	Industrial Revolution	03.0	Mass production allows for product standardization, bringing the germ of industrial revolution and steam power.
06	11,900 HE(1900 CE)	Technological Revolution	04.0	Transition to industrial revolution is complete, bringing plastics, radio and other such inventions.
06		(Age of electrical energy, mass communication, and the widespread use of the engine)	05.0	Widespread electrification, tele-communications and internal combustion.
07	11,950 HE (1950 CE)	Early Atomic & Space Age	06.0	Development of fission power
08	12,000 HE (+2000 CE)	Information Age & Commercial Space	06.5	and more advanced computing.
09	12,050 HE (+2050 CE)	New Space Race	07.0	Can reach orbit reliably and has telecommunications satellites.
10	12,100 HE (+2100 CE)	Cis Lunar Space Development.	08.0	Possible to reach other worlds in the same system, although terraforming or full colonization is not within the culture's capacity.
11	12,200 HE (2200 CE)	Interplanetary Settlement and Mega Structure Age. The ability to build infra and mega structures in space.	08.5	(Planetary Colonization)
12	12,300 HE (2300 CE)	Post Earth Dependence. Intrastellar Economy can survive without earth.	09.0	Space travel is vastly safer and faster; first steps into Jump Drive technology.
13	12,400 HE (2400 CE)	Outer System Development. Stable Jump travel to Outer systems.	09.5	(Conquest of the Solar system)
14	12,500 HE (2500 CE)	Early Interstellar Trade and Exploration Era.	10.0	With the advent of Jump, nearby systems are opened up.
15	12,600 HE (2600 CE)	Interstellar Colonization.	10.5	(Interstellar Colonization)
16	12,700 HE (2700 CE)	Self-sufficient Megastructures and Swarms.	11.0	The first primitive (non-creative) artificial intelligences become possible in the form of “low autonomous” interfaces, as computers begin to model synaptic networks.