Greetings
Romie,
Actually, a broadly all right SSC given what we are told, but some comments. I see you included the very link
t00fri mentioned in the InfoURL anyway, but how come some numbers differ slightly?
Mass. The Exoplanet site states mass of 'e' is 0.006104 ? Jupiter's mass = 1.94 Earth's mass. Although errors are not given (yet) on the Exoplanet site, it's wise to keep precision throughout calculations until the final answer.
Radius. It is usually a big mistake to assume radius varies as mass: 12,160km is clearly 1.9
0 ? 6,378km. You've just made your planet 'e' as undense as petrol! Radius would scale as the cube root of mass when keeping the same average density. Probably bigger planets are more dense. Let's allow density to be proportional to mass: then radius scales as fourth root: 1.94^(1/4) = 1.1802. Likely radius 1.1802 ? 6,378km = 7,527km.
Period. 3.14942 divided by 365.2564 days gives 0.008622 years. You had 0.00862
7 years. This time there's an error (±0.000001232 years), but it's negligible compared to the precision we've been given, so it's important to keep the digits correct to this precision.
Semi-Major Axis. This is tricky. The precision of reported values is deliberately kept low because of uncertainty of the star mass (we are tossed a low precision "0.31"). Yet to be consistent, if 'd' is at 0.22 A.U., and given the ratio of orbital periods for 'd' and 'e', 'e' must be at 0.029 A.U., not 0.030 A.U. (0.03 and 0.030 are Not The Same Thing!).
Eccentricity. There's no reported detection of eccentricity. Why 0.01? It should be just 0.
Rotation. "# likely to be in captured synchronous rotation". Yes! Very likely! I think tides from 'b' are too weak compared to those from the star to spoil that, even though 'b' appears three times larger at opposition than our full moon!
Texture. "... exact texture ..." Interesting concept
. A surface texture might not be needed: we could have an ocean world, with 100% cloud cover. I suspect that for the estimated age of Gl. 581 at 8 billion years (11 billion years upper), any global ocean being lost through a Venus-like wet runaway greenhouse would still exist if it started off deeper than 320km (~450 km upper) (assuming Venus lost an Earth-comparable 4km deep ocean in 100 million years - I have to refresh myself on that). That could be quite possible, but the alternative is the oceans are gone and we have a dry greenhouse just like Venus. An ocean texture is much easier than a land texture
. In any case, as I say, the most likely appearance of 'e' would be 100% coverage by uniform white clouds.
So...
Code: Select all
"e" "Gliese 581" # HO Lib
{
Texture "Gl581-e-ocean.*"
Atmosphere {
# blah blah blah
Cloudmap "Gl581-e-clouds.*"
}
Mass 1.94 # M.sin(i) = 1.94 Earth masses.
Radius 7527 # Guesstimate from taking fourth root of mass ratio to Earth.
InfoURL "http://exoplanet.eu/star.php?st=Gl+581"
EllipticalOrbit {
Period 0.008622
SemiMajorAxis 0.029
Eccentricity 0
}
# Likely to be in captured synchronous rotation.
}
Spiff.
ahhh so much petrol, $$$$ 
Also, I imagine it might even be possible that future observations would allow us to determine the orbit of the Earth more precisely and revise the length of the J2000 sidereal year. Better just to use a convenient multiple of the SI time unit and be done with it.