Dragaera

Speculative Planetary Statistics for Dragaera (Math help?)

Thu Apr 6 13:24:03 PDT 2006

All the math checks out.  One thing I noticed is that the axial tilt  
is rather higher than Earth's -- and I don't recall seasons on  
Dragaera seeming any more severe than those on Earth (hard to  
compare, though).  I think the spectral type of Dragaera's sun would  
be a bit later, maybe a G5 or so.

You can find the orbital distance by using Kepler's Third Law: a^3 =  
M*P^2/Msun, with a being the average distance from planet to star in  
astronomical units (the Earth-Sun distance being one AU), P being the  
period in years, M being the star's mass, and Msun being the Sun's  
mass.  The planet's mass actually doesn't matter, since it's so small  
compared to the star's.

  You can get an average velocity by just taking the orbit's  
circumference, and divide by the period.  For a more exact  
calculation, you can use the vis viva equation:

v = (G * M * (2/r - 1/a)) ^ 0.5, G being Newton's Gravitational  
constant, and r being the planet's current distance from its star.

Most useful are the maximum velocity vmax = (G * M /(a(1-e)) ^ 0.5  
and minimum velocity vmin = (G * M /(a(1+e)) ^ 0.5, with e being the  
eccentricity.

Any other useful equations you need?

-- Rebecca Harbison

On Apr 6, 2006, at 3:26 PM, Jon_Lincicum at stream.com wrote:

> Inspired by the "Small Invisible Lights" website going away, I've been
> working on porting some of the Dragaera information this site used to
> provide into the wikicity.
>
> Having some free time, I've been trying to figure out some of the
> planetary stats for Dragaera. (SiL used to have a page about the  
> Dragaeran
> planet and star, such as its orbital tilt, etc.)
>
> This led me to want to create at least speculative values for some  
> of the
> other planetary characteristics of Dragaera.
>
> The result is a (admittedly preliminary and somewhat dubious)  
> speculation
> page about Dragaeran planetary stats on the wikicity:
>
> http://dragaera.wikia.com/wiki/Speculation:Dragaera
>
> What I'm really looking for at this point, is either someone to  
> check my
> math (haven't done any real math work since college, lo these many  
> years
> ago, and it isn't a major area of study for a Music Major like myself,
> anyway) as well as maybe provide some clues about how to calculate the
> orbital velocity of a planet when you "know" the mass of the star, the
> planet, and the duration of the oribtal period.
>
> Any help or advice is appreciated. Thanks!
>
> Majikjon
> listinfo/dragaera
>
>