First In statistics

This analysis is aimed specifically at finding the statistical distribution of habitable worlds
produced by the rules in GURPS Traveller: First In
, pp. 44-58, 67-76, 91-92.

The figures are on a per-star, rather than a per-system, basis because spectral type is the 
single most influential variable throughout. To keep the amount of calculation under control, I 
did not consider worlds around Class A or M stars, nor worlds that fall outside the habitable 
zone defined on p. 54.


Step 1:

Multiple Stars: 

Single	0.500
Double	0.418
Triple	0.063
Quad	0.018

Average: 1.587 stars/system


Steps 2-3:

Luminosity Class:  Class V (Main Sequence) = 0.866

Spectral Type:

F0	0.0293
F5	0.0293
G0	0.0671
G5	0.0671
K0	0.100
K5	0.100

These account for the distribution of both primary and companion stars.


Steps 4-5:

Open orbits in multiple star systems:

	1st Companion	2d Companion	3d Companion
F0	0.5236		0.9569		0.7470
F5	0.5987		0.9763		0.6027
G0	0.6228		0.9858		0.3860
G5	0.6536		0.9911		0.2173
K0	0.7325		0.9953		0.1792
K5	0.8415		0.9987		0.2217


Steps 6-7:

Fraction of random orbits that fall in the habitable zone:

F0	10/18
F5	14/18
G0	11/18
G5	18/18
K0	11/18
K5	6/18


Step 8:

Habitable zone orbits are filled by:

Gas Giant	0.018
Planetoid Belt	0.229
Planet		0.753

Moons of gas giants can be large enough to be habitable, but their numbers are statistically 
insignificant.


Steps 9, 12-16:

Earthlike worlds have Standard size (p. 67), non-zero hydrographic coverage, and some kind of 
native life:

F0	0.107
F5	0.283
G0	0.345
G5	0.365
K0	0.365
K5	0.365

I calculated Diameter in round 1,000's of miles, only. Earthlike worlds resulted for 
D = 5,000-10,000. Likewise, I only calculated Hydrographics in multiples of 10%.

0% Hydrographic Coverage: 0.0219

Earthlike worlds with a Very Thin atmosphere: 0.0776


Taken all together:

Habitable worlds: 	0.0399 per star
			0.0633 per system

Intelligent native life:	0.00294 per habitable world
				1 per 339.7 habitable worlds

Stars, by class, with habitable worlds:

F0   0.0267
F5   0.1027
G0   0.1001
G5   0.1765
K0   0.1118
K5   0.0637

Habitable worlds around each class of star:

F0   0.0196
F5   0.0754
G0   0.1683
G5   0.2968
K0   0.2808
K5   0.1598

Habitable worlds in multiple systems:

Single     Multiple
0.5980     0.4020



Step 19:

MSPR for habitable worlds:

Atmospheric Pressure

Thin (-1)	Standard	Dense		V. Dense (-1)
0.3302		0.4525		0.1460		0.0714

Hydrographics

10-30% (-1)	40-80%		90-100% (-1)
0.2249		0.6550		0.1201

Atmospheric Composition

Polluted (-1)	UnPolluted
0.3750		0.6250

Climate

238K- (-2)	0.0038
239K-260K (-1)	0.1191
261K-319K	0.8556
320-324 K (-1)	0.0110
325K+ (-2)	0.0105


MSPR		3d
9	0.1585	3-7
8	0.3944	8-10
7	0.3251	11-14
6	0.1073	15-16
5	0.0137	17
4	0.0010	18