Num Star Age ZMass Mass ZLum Lum Rad Met Pha
73 G0 V 4.064 1.048 1.048 0.9180110 1.2904449 1.071 2 1
ZAMS Inner Zone = 0.789 Current Inner Zone = 0.926
ZAMS Hab Zone = 1.580 Current Hab Zone = 1.856
ZAMS Earth Equiv= 0.958 Current Earth Equiv= 1.136
ZAMS Outer Zone = 2.429 Current Outer Zone = 2.880
Num AU ecc type mass den rad peri aph hill inner outer 4:1 2:1 migrate
1 0.200 0.072 4.000 0.000 0.000 0.000 0.186 0.214 0.001 0.182 0.216 0.079 0.126 0.842
2 0.360 0.068 4.000 0.000 0.000 0.000 0.336 0.384 0.001 0.330 0.388 0.143 0.227 0.842
3 0.576 0.005 4.000 0.000 0.000 0.000 0.573 0.579 0.002 0.568 0.584 0.229 0.363 0.842
4 1.094 0.079 4.000 0.000 0.000 0.000 1.008 1.181 0.003 0.991 1.191 0.434 0.689 0.842
5 6.263 0.027 3.000 8.312 10976.350 70017.000 6.095 6.430 0.853 2.684 8.989 2.485 3.945 0.842
6 11.273 0.084 2.000 0.221 560.300 56320.500 10.324 12.222 0.458 8.034 13.596 4.474 7.101 0.842
7 22.546 0.079 2.000 0.149 988.400 40850.500 20.763 24.330 0.803 16.748 26.738 8.947 14.203 0.842
8 38.328 0.069 1.000 0.183 1734.060 36280.000 35.700 40.957 1.462 28.390 45.343 15.210 24.145 0.842
4 AA858BA-A (Temperate) Ri Ga
First, here's what turns out to be a pretty habitable system, not too different to our own solar system!
The primary star is a solo G0 V, somewhat brighter and a little more active than our own sun, and has a similar metallicity. It's about halfway through its main sequence lifespan (its total lifespan is a bit shorter than Sol's) but generally pretty stable. It's got a bit brighter since it formed, which has pushed its orbital zones outwards from their initial locations (not to the detriment of any of its planets though).
The planetary orbits are pretty stable and not very eccentric. The jovians did start out a little further from the star and migrated inwards by about 84% of their initial distances, but stopped before they could mess up rocky planets in the inner system.
Planet 1: Tidelocked Greenhouse Hellhole. It's pretty much exactly like Venus, but even hotter and tidelocked (with earthlike density). This close to the star the atmosphere might be a bit thinner, but the base temperature (without greenhouse effect) is still about 664 K. There's ferocious winds from the dayside to nightside that keeps the planet at a uniform temperature, probably around 800-900 K. Not a nice place to be.
Planet 2 and 3: Pretty much identical rockballs. Both worlds are tidelocked rockball with no atmospheres, though the inner world is somewhat denser than the outer one.
Planet 4: Jackpot!
Somewhat larger and denser than Earth (8000 km radius) and with a surface gravity of 1.37G, this planet is half covered by oceans and has a dense, breathable atmosphere and earthlike temperature extremes. It is geologically active world with plate tectonics and volcanoes, and probably a large moon too (which seems to be a necessity for life). At just over 4 billion years old, it's a few hundred million years younger than Earth - and when Earth was 4 billion years old we were in the Cambrian era and complex life was just starting!. However, I'll say that this planet's a bit more advanced than that, and already has a decent biosphere in land and sea (roughly equivalent in complexity to the Permian era on Earth), so there's oxygen in the air, lots of sea life, amphibians, reptiles and dinosaur equivalents on land. The air is about 10% O2, with about 85% N2 and 5% Helium (which makes for somewhat vivid aurorae), but the dense atmosphere increases the oxygen pressure enough for it to be breathable unaided by humans. A few hundred million people call this world home, and enjoy a high TL and have a fully functional starport and shipyard.
Planet 5: About 5 AU further out from our habitable world orbits a monstrous hyperjovian. Weighing in at over eight jupiter masses (crammed into a body that's the same size as Jupiter, so it's much denser), this planet's gravitational influence ejected a LGG from the system that was in an orbit between it and the rockies (which explains the large orbital gap). The hyperjovian emits a lot more radiation than it receives from its primary star, and early in its history was certainly warm enough to drive off ice in the inner part of its protojovian disk - its moons are therefore likely to be rocky bodies, and given the jovian's mass they can potentially be the size of full blown planets (up to size 6-8). However, the moons themselves will be very cold and ice-covered (surface temperature is around 120 K).
Planets 6 and 7: These two Hydrogen Giants (LGGs) have unusually low densities, and are very similar to (but slightly smaller than) Saturn in the Sol system. They also have moons and probably spectacular ring systems. The second giant is just on the borderline of being classed as an SGG.
Planet 8: The outermost planet is a large Icy Giant (SGG) somewhat larger than but similar to Neptune in the Sol system. It's 4000 km smaller than Planet 7, but it's so dense than it's actually more massive than the inner planet. Like Neptune, it's wracked by storms and probably has a small family of moons.One thing you should note though
- this sort of system is pretty rare in my worldgen. I'll be posting some more examples of the more common ones, but here we have a relatively rare star (a G V), that's about the right age for habitable planets, that doesn't have jovians in the wrong places screwing things up, that actually has a large planet in its habitable zone, which also has managed to generate a breathable atmosphere. There's a lot
of things that could prevent a habitable planet from forming in a system, but this one happens to have - entirely by chance - got everything conspiring to allow a habitable planet to form.
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