Planet Generation

[Noven]

I generated a planet and system using Space for a fantasy game idea that I have and I wanted to share the results with you all since the ending result was very interesting. Also, for the scientists out there, I wanted some input on how the world would be acting from a meteorological and geological standpoint.

Note: I have not generated the other planets yet, and was not going to do that today.

Source

Zeta Tucanae System Information
Number of Stars: 1
Star Mass

    * Primary Star Mass: 1.15
    * Star System Age: 4.4 billion years

Stellar Characteristics


Primary Star Luminosity Class V (Main Sequence)

    * Spectral Type: F9
    * Effective Temperature: 6100 K
    * Current Luminosity: 2.18805970149253731343
    * Star Radius: 0.00616171507211541672 AU
    * No Gas Giant Arrangement 


Orbital Zones

    * Star Inner Limit Radius: 0.115 AU
    * Star Outer Limit Radius: 46 AU
    * Star Snow Line: 7.1741643644649102056 AU

Zeta Tucanae
	Orbital Radius
Asteroid Belt 	0.189508194 AU
1st Orbit: Small Planet () 	0.37901639 AU
2nd Orbit: Standard Planet () 	0.720131137 AU
3rd Orbit: Standard Planet (Garden) 	1.296236046 AU
4th Orbit: Small Planet () 	2.203601278 AU
Asteroid Belt 	4.407202556 AU
5th Orbit: Small Planet () 	7.932964602 AU
6th Orbit: Standard Planet () 	12.69274336 AU
7th Orbit: Standard Planet () 	22.84693805 AU
Asteroid Belt 	38.33333333 AU

Source

3rd Orbit of the System
Standard Planet: Garden
Orbital Radius: 1.29623604614966835971 AU
Blackbody Temperature: 297.00413223140495867769 K
Average Surface Temperature: 299 F
Climate: Normal
Atmospheric Pressure: 0.85344001880769531842 (Standard)
Atmospheric Mass: 0.9
Hydrographic Coverage: 70%
Density: 0.9
Diameter: 1.05362965284900656596
Surface Gravity: 0.94826668756410590936 G
Mass: 1.05270446152160816144
Resource Value Modifier: Abundant (+1)
Planetary Orbital Period: 502.66579768598065420282 days
Minimum Separation: 1.10180063922721810575 AU
Maximum Separation: 1.49067145307211861367 AU
Tidal Effect: 11.0899296196474135365
Sidereal Period: -1.17041373415197556402
Local Calender: 1.17314530128684505372 days Retrograde (28.15548723088428128928 hours)
Axial Tilt: 7°
Volcanic Activity: Moderate
Tectonic Activity: Light

Tiny Moon (Rock)
Orbital Radius: 26.340741321225164149
Blackbody Temperature: 296.97339284335141225214 K
Average Surface Temperature: 285.09445712961735576205 K
Climate: Cool
Atmospheric Pressure: Trace
Atmospheric Mass: Trace
Hydrographic Coverage: 0%
Density: 0.4
Diameter: 0.17438484861695750147
Surface Gravity: 0.06975393944678300059 G
Mass: 0.00212122255991816545
Resource Value Modifier: Average
Tidal Effect: 370866.55792795458537341932 (Tide-locked)
Tidal Force Exerted: 2.17675847605174376161
Satellite Orbital Period: 7.73978627222668349991 days
Volcanic Activity: None
Tectonic Activity: None

[Agemegos]

Calculate the temperature at apastron (maximum separation) and periastron (minimum separation). You will find the result interesting.

[David Johnston2]

That's not so easy. The thing you have to remember about elliptical orbits is that the part of the orbit which is near the Sun is a shorter period than the part of it which farther out than the median distance. Therefore winter (which thanks to a lack of axial tilt is produced by being actually remote from the sun) is, generally speaking, longer than summer. Northerly climes will be _very_ uninhabitable in the depth of winter, which lasts a long time due to the 2x year length. I wouldn't surprised to see hibernation as a common trait in northern animals.

[Noven]

Originally Posted by Brett

Calculate the temperature at apastron (maximum separation) and periastron (minimum separation). You will find the result interesting.

Umm, how do I do that? I didn't see that in Space

[Noven]

Ok I go the temperatures, and wow, maybe I should tone down the eccentricity

[RyanW]

A planet functions as a substantial heat sink, so living on an eccentrically orbiting planet won't be quite as extreme as summering on Venus and spending the winter on Mars.

[David Johnston2]

Stay away from deserts on the interior of a continent, though.

[Flyndaran]

Originally Posted by RyanW

A planet functions as a substantial heat sink, so living on an eccentrically orbiting planet won't be quite as extreme as summering on Venus and spending the winter on Mars.

True, but who wants runaway greenhouses in summer, and runaway glaciation in winter? Exactly how much a life bearing planet can "hold" it somewhere in the middle is anyone's guess.

[Agemegos]

Originally Posted by Noven

Umm, how do I do that? I didn't see that in Space

I see that you worked it out.

It isn't in Space, probably because it is a bit tedious to do it until you automate the sequence and get a computer to crunch the numbers.

If it had been in Space I think playtesting might have driven the authors to reconsider their table for orbital eccentricities. The eccentricities are simply treated as decorative in the RAW. But if you follow the consequences through it makes you wonder about the calculated Habitability ratings for a lot of these planets.

Originally Posted by Noven

Ok I go the temperatures, and wow, maybe I should tone down the eccentricity

I'm really not sure whether the system generation system in Space makes orbital eccentricities too high. The values in our solar system are 0.2056, 0.0068, 0.0167, 0.0934, 0.0483, 0.054, and 0.006. And Mercury's high value is perhaps not randomly-placed: there are orbital interactions that tend to even out the spacings of orbiting satellite, moving the inner ones in and the outer ones out,and they also tend to make the orbits more circular for planets or moons that have something orbiting on each side of them, inwards and outwards. Perhaps a planet in the Goldilocks zone, likely to have another planet in orbit sunwards and another darkwards, should not have a chance of an eccentric orbit anything like Mercury's. Or even Mars's.

One thing that I am pretty sure of is that Space makes "eccentric gas giant" and "episolar gas giant" systems far more common than they are in reality. I understand that it has been established from surveys of nearby stars that no more than 3–6% have detectable (ie. epistellar or eccentric) gas giant planets. If you modify the "Gas Giant Arrangement Table" on p. 107 to

Roll (3d6) g Arrangement
5 or less gapp no gas giant
6 – 15 gapppp conventional gas giant
16 gapgapgap eccentric gas giant
17 – 18 gappp epistellar gas giant

your results will be more realistic and habitable.

Originally Posted by RyanW

A planet functions as a substantial heat sink, so living on an eccentrically orbiting planet won't be quite as extreme as summering on Venus and spending the winter on Mars.

No, but it could be pretty bad. The temperature extremes of day and night are mild compared to those estimated for the dayside and nightside of a tide-locked planet, but they are not negligible. Annual temperature variations due to eccentricity are not as strongly-driven as that, but on the other hand they get more time to build up.