Class IV gas giants

Refuge, the moon that Sarah Dayson finds and determines is the future for her fleet crew, is a living breathing world.  Much larger than Earth, it's less dense and therefore the gravity isn't too out of control.  1.16G is what the math tells me.

Today I took the liberty of downloading a free wallpaper and modifying it with ArtRage Pro to depict what I think the sky might look like on Refuge.  The large planet in the sky is tentatively called Hades by Sarah's crew, although I might yet change that name.  It seems a bit cliche, but it does fit the planet 100%.  Hades is a Class IV gas giant, over 11 Jupiter (Jovian) masses, and still retains so much heat from its original formation that it glows in ruddy red light on the dark side.  I can imagine this baleful red light casting shadows on the lands of Refuge when Refuge is behind Hades and not lit by sunlight.  Hades is about 190,000 miles in diameters, which means it is about 1/5th the diameter of our sun, Sol.  Refuge is very close to Hades, about 1.1 million kilometers, so the heat from the planet plays a part in keeping the moon warm enough for life.

Class IV gas giants are very dark.  Because of the high temperature of a class IV gas giant, complex molecules are rare.  Instead of quantities of methane and other hydrocarbons in the atmosphere like Jupiter has, the predominant carbon molecule is carbon monoxide.  Many metals are at temperature that make them gaseous in the core, only to condense out in the upper clouds and rain down as liquid metal rain.  In a class IV gas giant that is probably sodium, potassium, and cloud decks of gaseous iron and other metals deeper inside the planet.  The upper cloud decks would be alkali metals, which would make the world dark like charcoal because these metals absord most light.  They'd reflect just 3% of the light that hits the planet.  The apparent surface temperature would be between 1,100 degrees Farenheit and 2,000 degrees Farenheit.

That's hot.  Hot enough to warm a close moon nicely, I'd think.

The other object in the sky of my creation below is the moon just inside Refuge's orbit, tentatively called Fandama, the local goddess of beauty.  Since Refuge is tidally locked to Hades, the planet is always in the same place in the sky.  The side of Refuge facing away from Hades would be considerably colder than the side facing the gas giant.  With a day/night cycle of 2.5 days (the time it takes for Refuge to orbit Hades) the side of the moon away from Hades would have time to get quite cold in the 30 hours or so of darkness that would come each night.  On the side facing Hades, there would be two days and two nights when Refuge passed through Hades's shadow, and only one when the tilt of Refuge's orbit kept it above or below that shadow.  I intend to do all the math on this at some point and let you know just how that day night cycle would work, because it's integral to the societal development of the natives. 

This is my first created visual image of my world and the universe that Sarah Dayson lives in.  I hope you enjoy what streams from my imagination both visual and written.  Click the image to enlarge it.

Hades warms the skies of Refuge, creating updrafts and rising storms.  Fandama graces the sky with her beauty. 

There would, of course, be no individual stars in the sky of Refuge other than their sun.  There would just be a washed out haze where the Milky Way glowed in the distance, along with the other moons of Hades and the other planets of the star Hades orbits.

I can imagine Fandama being a world not unlike Venus, overheated from being 600,000 kilometers from Hades.  Life on a world such as Refuge would be interesting, with the varied day/night cycles and the constant dance of Hades and the moons in the sky.  Days might get quite warm, nights quite cold.  But a thick atmosphere and a large oceanic mass allow the moon to moderate the extremes and distribute the heat differentials to create a reasonable climate for life.

Welcome to Refuge.