Planets of Alpha Centauri

Solar constants Sun Alpha A Ratio

Mass kg 1.99E+30 2.15E+30 1.08

Luminosity W 3.89E+26 5.63E+26 1.45

Radius m 6.96E+08 7.59E+08 1.09

 

Planetary constants Earth Planet/ Ratio

Chiron

 

Mass kg 5.98E+24 1.10E+25 1.84

Equat. radius m 6.38E+06 7.54E+06 1.18

Dist. from star m 1.50E+11 1.60E+11 1.07

Axial tilt degrees 23.45 2.00 0.09

Surface area m2 5.10E+14 7.18E+14 1.41

Standard gravity m s-2 9.81 12.85 1.31

Escape velocity m s-1 11184 13947 1.25

Density kg m-3 5519 6150 1.11

Size of sun degrees 0.27 0.27 1.02

Year our days 365.3 388.6 1.06

Year local days 365.3 532.0 1.46

Day hours 24.00 17.53 0.73

Mountain height m 10626 8112 0.76

Horizon distance m 5051 5493 1.09

Ocean tide (sun) m 0.12 0.12 0.94

Ocean tide (moon 1) m 0.27 0.18 0.67

Ocean tide (moon 2) m 0.11

Ocean tide (both) m 0.39 0.41 1.05

 

Atmosphere

 

Total pressure Pa 101325 176020 1.74

Nitrogen Pa 79125 160000 2.02

Oxygen Pa 21228 15000 0.71

Argon Pa 942 1000 1.06

Carbon dioxide Pa 30 20 0.67

Nitrogen 78.09% 90.90% 1.16

Oxygen 20.95% 8.52% 0.41

Argon 0.93% 0.57% 0.61

Carbon dioxide 0.03% 0.01% 0.4

Surface density kg m-3 1.22 2.06 1.68

"Flammability" mmol K J-1 7.17 2.87 0.40

Effective temp. K 253 261 1.03

Greenhouse effect K +36 +32 0.90

Surface temp. K 288 293 1.01

Surface temp. C 15.4 19.7 1.28

Solar constant W m-2 1383 1750 1.27

 

Moon #1 (Nessus) The Moon Nessus

 

Mass kg 7.35E+22 6.50E+21 0.09

Radius m 1.74E+06 8.00E+05 0.46

Dist. from planet m 3.84E+08 2.00E+08 0.52

Surface area m2 3.80E+13 8.04E+12 0.21

Mean gravity m s-2 1.62 0.68 0.42

Density kg m-3 3342 3031 0.91

Synodic month our days 29.5 7.7 0.26

Synodic month local days 29.5 10.6 0.36

Syn. months/yr 12.4 50.2 4.05

Angular radius degrees 0.26 0.23 0.88

 

Moon #2 (Pholus) The Moon Pholus

 

Mass kg 7.35E+22 5.20E+20 0.01

Radius m 1.74E+06 3.50E+05 0.20

Dist. from planet m 3.84E+08 1.00E+08 0.26

Surface area m2 3.80E+13 1.54E+12 0.04

Mean gravity m s-2 1.62 0.28 0.17

Density kg m-3 3342 2895 0.87

Synodic month our days 29.5 2.7 0.09

Synodic month local days 29.5 3.7 0.13

Syn. months/yr 12.39 143.76 11.60

Angular radius degrees 0.26 0.20 0.77

 

Eurytion (Mercurian planet) Earth Eurytion Ratio

 

Mass kg 5.98E+24 5.16E+23 0.09

Equat. radius m 6.38E+06 2.82E+06 0.44

Dist. from star m 1.50E+11 7.06E+10 0.47

Surface area m2 5.10E+14 9.98E+13 0.20

Standard gravity m s-2 9.81 4.33 0.44

Escape velocity m s-1 11184 4942 0.44

Density kg m-3 5519 5503 1.00

Size of sun degrees 0.27 0.62 2.31

Year our days 365.3 113.8 0.31

Year local days 365.3 SYNCHRONOUS

Horizon distance m 5051 3357 0.66

Surf. temperature K 288 438 1.52

Surf. temperature C 15.4 165.3 10.71

Solar constant W m-2 1383 8999 6.51

calcium carbon lime silica

silicate dioxide

From Brian Reynolds of Firaxis (Message Board Post - 20 July 1998)