Planetary mechanics. Please help. Physicists, Astronomers, People Who Study This Kind of Stuff

In a previous post, I wrote about the pretty cool Alternity universe creator for that RPG.

It occurred to me that many random readers may have experience or interest in the mechanics of the heat or lack thereof in a planetary mass, and how that would affect weather on that planet (assuming a lot of factors here).

So here’s the system:

The star is a Class K Red Giant Mature. Temp is 4500 K, mass is 2x Sol, radius is 30x Sol, luminosity is 200 x Sol.  The star is a monster, isn’t it?

So here’s the stats of the planet:

Deep system Orbit 16.03 AU Temperate zone Terran
Type Terran
AU 16.03
angle 331
orbit circular
Perhilion 15.9
Aphelion 16.2
YEARS 61.5

Axial Tilt (earth=23) 13
Rotation (hours) 36 hours
Mass (earths) 0.3
Diameter 11032 km
Gravity 0.9
water arid 20%
magnetism 1 gauss
Atmos: 4 PO

Does anyone just happen to have a planetary weather generator where you plug in the above numbers and it just sort of tells you what the average temperature is at different times? (I jest. Such a thing probably doesn’t exist.) If earth experiences a fluctuation in temperature just from the perihilion/aphelion orbital mechanics, wouldn’t a larger variation in the planetary path cause much wider variations of the planetary atmospheric temperature?

I totally get why authors might just have all the planets be Earth Standards with atmo, gravity, and temps the same.  The more extreme the environment, the more it factors in to what you write, because you have to protect your characters from the weather by telling the reader what you’re doing.  Or you gloss over it and invent a shield or piece of clothing that allows them to ignore the weather and go about the business of advancing the plot.  [There’s probably a trope name for that.]

Go ahead, comment. It won’t kill you.  And, um, it’s not because I’m desperate. Because I’m not. I’m NOT! Just comment. If you comment, I’ll be your best friend!  C’mon. I’ll give you a cookie! Yeah, I love the “Don’t Let the Pigeon Drive the Bus” books, too.

3 thoughts on “Planetary mechanics. Please help. Physicists, Astronomers, People Who Study This Kind of Stuff

  1. I suppose you can get away with a lot here, and make it believable -I mean, it is fiction, after all. One thing that struck me though was the Mass vs. the Gravity. .3 Earth / .9 Earth. That seemed wrong to me. I spent entirely too long trying to work out how to get there, and came to the conclusion that your planet would need to be mostly made of elements roughly heavier than nickel. I think this is a density similar to an asteroid. A planet like this would surely be packed full of rare-earth elements, and be more metal than anything, perhaps a few shallow oceans? It seems like this would have some odd effects on weather given that the Earth’s deep and expansive oceans have a great deal of influence on moderating weather. I would imagine your planet as being mostly dry and harsh, not particularly hospitable for life. If the nature of the weather is unclear, it would almost certainly be highly predictable. Small patches of less dense rock/dust might gather in protected valleys and canyons. These might be safe harbors for life. Anyhow, just a thought.


    • I wasn’t sure how the mass/gravity would affect the makeup of the place – I’m no astronomer so I lean heavily on the work of others to have it make sense. If something wasn’t useful for growing food, then it only has two other applications – mining and fuel. It seems cheaper to mine something in microgravity rather than spending fuel and money to mine in gravity with the cost of removing it from a gravity well.

      So, cold dust storms. Or not. I suppose I should take a look at how the oceans affect weather here, and then find a dry arid place and look at the weather there, for instance, Mongolia, or the Russian steppes. Neither one is near a large body of water, and that’s going to be my model, I think. The hook is that the planet is mined and manufactures HCA and thus has value from that, but the food is greenhoused/algea based, depending on how rich you are.

      Open pit mines, then, since there’s no beautiful nature to destroy here, and if it leaves ugly gashes on the planet, so what? Mines >> Manufacturing. I’ll use the old standby of “this planet has unobtanium” trope to justify an economy of anything here. Plus it’s livable. Not everybody has a breathable atmosphere. The water is rare – arid, so that’d be a commodity used sparingly.

      Liked by 1 person

      • I think this planet would have an amazing mineral-extraction economy. Plus if there were anywhere in the universe with easy to get at ‘unobtanium’ it would be this place. Good luck with it!


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