Which Stars Would Best Suit For the Habitable Zone of The Nine Norse Earths?

In an alternate universe, the nine realms of Norse mythology--Midgard, Asgard, Vanaheimr, Jotunheimr, Alfheimr, Hel, Nidavellir, Niflheim and Museplheim--are actual, real-life "Earths", in the sense that all of them have the exact same features listed below:

• At least one large natural satellite, one-quarter the diameter and 1/80 the mass, to stabilize the parent's axial tilt
• A predominantly iron core, meaning a strong, active magnetic field
• An inner core measuring a radius of 760 miles
• An outer core measuring 1367 miles thick (I don't know why Google doesn't have its width, which is what I really needed.)
• A predominantly silicon crust
• A predominantly silicon-magnesium mantle
• Atmospheric pressure no greater than one bar
• Clear, tangible evidence of life (albeit microbial at this point, but with the dark power of illegal multi-tiered terraforming, anything is possible.)
• A crustal diameter anywhere between 7,520.8 miles ("Venusian") and 7,917.5 miles ("Terran"), with the sole exception of Jotunheim, who measures at a diameter of 4,212.3 miles ("Martian")
• Mass ranging from 0.8 to one Terran, though Jotunheim has a mass almost 11% that of Earth's
• Active tectonic plates

Now, having nine "Earths" requires a very wide habitable zone, in which liquid water is possible. So I have eliminated all the candidates in the search for all the star types that are both bright and long-lasting. Only two types remain:

1. G-type main-sequence stars, or "yellow dwarves"
2. K-type main-sequence stars, or "orange dwarves"
3. A mix of both

You could have the Nine Earths orbiting giants that are hundreds of times more luminous than the sun, but larger stars have shorter lifespans. Red dwarves are small enough to live trillions of years, but they are unacceptably dim and constantly lash out deadly radiation.

So how many yellow dwarves, orange dwarves, or a mix of both, would be required to have the luminosity to have a habitable zone of either four or 14 astronomical units (372 or 1,302 million miles)?

posted over 4 years ago

JohnWDailey‭

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