User:Ceciri/SandboxThree

Ceciri/SandboxThree
{{{image}}}
Astrographical Information
Region	{{{region}}}
Sector	{{{sector}}}
System	{{{system}}}
Sun(s)	{{{suns}}}
Moon(s)	{{{moons}}}
Orbital Radius	{{{radius}}} AU
Eccentricity	{{{eccentricity}}} AU
Periapsis	AU
Apoapsis	AU
Inclination	{{{inclination}}}
Orbital Motion	{{{inclination}}}
Class	{{{class}}}
Physical Parameters
Diameter	{{{diameter}}}
Atmospheric Contents	{{{atmosphere}}}
Atmospheric Mass	{{{atmmass}}}
Avg Atmospheric Pressure	{{{atmpress}}} standard, ( hPa)
Hydrosphere	{{{hydrosphere}}}
Climate	{{{climate}}}
Blackbody Temp	{{{blackbody}}}°K (-272.15°C)
Gravity	{{{gravity}}}
Primary terrain	{{{terrain}}}
Points of interest	{{{interest}}}
Length of Day	{{{lengthday}}}
Length of Year	{{{lengthyear}}}
Native species	{{{species}}}
Other species	{{{otherspecies}}}
Societal
Official Language	{{{language}}}
Population	{{{population}}}
Technological Classification	{{{techclass}}}
Major cities	{{{cities}}}
Imports	{{{imports}}}
Exports	{{{exports}}}
Affiliation	{{{affiliation}}}
Government	{{{government}}}

This template is meant to display all information on a planet. It leaves certain arguments out since we aren't interested in precise navigational details (that's why ships have a navcomp), but has certain advanced astrophysical arguments. To help the person using this template, we have a guide of what each argument is, below:

Orbital Arguments

First off, we examine the primary arguments. These are orbital radius (often referred to as the semi-major axis), eccentricity and inclination (there are several others, such as true anomaly, mean anomaly, longitude of ascending node, argument of perihelion, but these are a bit more advanced and not included in the template for various reasons.)

To calclulate these you will want the star's mass and luminosity. I'll try to give average suggestions, as well.

The first one, is orbital radius (the parameter radius in the template), which is the average radius of the planet. It is also called the semi-major axis, due to the fact that planets orbit according to Kepler's Three Laws Of Planetary Motion

1. The orbit of a planet is an ellipse with the Sun at one of the two foci. 2. A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time. 3. The square of the orbital period of a planet is proportional to the cube of the semi-major axis of its orbit.

For an explanation of this, I strongly recommend you read the Wikipedia article linked behind. What this means for us is that it provides some bounds on the figures we can give.

For an orbital radius, it should be no less than .1 * the mass of the star, and no more than 40 * the mass of the star. This provides values in Astronomical Units (roughly 150 million km, or 92.95 million mi per AU)

If you have a habitable planet, it is probably best to be placed between .95 * square root of the star's luminosity, and 1.37 * square root of the star's luminosity in AU.

A gas giant should be placed at a little more than 4.85 times the square root of the sun's luminosity unless it is a hot jupiter, which should be very close to the inner radius. (Eccentric gas giants may be more random, however.)

Terrestial planets will generally not form beyond the frost line (and by generally not, I mean they really *won't*. Looking through exoplanet catalogues, there doesn't appear to be any found.) As such, if you don't care if it's habitable or not, place it randomly between the inner radius and the frost line.

Small icy planets should however, be placed beyond the frost line, as they will not form before (too warm) unless they have migrated inwards. (There are some "super earth" ice planets that may form out here too.)

The second orbital parameter is eccentricity. This one's simple. It measures how elliptical an orbit is, with values from 0 to 1. No planet orbits at 0 eccentricity - all orbits are an ellipse. But by the same token, an orbit at 1 or more is no orbit. 1 is a parabolic orbit, and over 1 is a hyperbolic orbit.

Generally speaking, anything near habitable planets (or /potentially near habitable planets) should have a capped eccentricity of .2 period. Gas giants will have lower values, and any hot Jupiter or close in planet to the sun will have very circularized orbits (somewhere between .00X and .0X eccentricity.) Habitable planets should have .0X to .1 maximum eccentricity.

The final one is inclination. This measures the orbit's difference from the system ecliptic, or the equator of the Sun. A quick primer on orbital inclination follows:

It is only between 0 and 180 degrees. 0 and 180 degrees are equatorial orbits. 90 degrees is a polar orbit. Anything over 90 degrees is a retrograde orbit. Anything below 90 degrees is a prograde orbit.

Generally, these are low values (most gas giants are less than 1 degree off), but it can be up to 10 degrees, if it orbits in the same direction of the sun's revolution (prograde) or between 170 and 180 degrees, if it orbits opposite the sun's revolution (retrograde)

(NB: The template will actually display the motion type automatically for you.)

Eccentric gas giants may have 0-30, or 150-180 degrees.

Now, with eccentricity, and radius, we can calculate periapsis (closest approach) and apoapsis (furthest approach). As long as you provide only numbers for both, the template will do the work for you (however, if you wish to do it at 'home', here are your formulas.:

• Periapsis: (1 - eccentricity) * orbital radius
• Apoapsis: (1 + eccentricity) * orbital radius.