Re: [Space] What is the 'Gaia' type of garden worlds like? ('Habitability 9').
 

You seem to be assuming two stars of equal radius and luminosity. A system with one large and bright star and one small and dim star will have less variability than that.

Re: [Space] What is the 'Gaia' type of garden worlds like? ('Habitability 9').
 

That's a hard balance to strike. The first configuration that comes to my mind as useful is a moon style setup: you orbit the small star, which orbits the big star. That leaves problems to be solved though, primarily how you avoid tidally locking the planet, and even if you solve that, giant tides aren't always the healthiest for humans.

Though if we're advocated lots of erosion as healthy that's one way to do it.

The way to counter tidal locking is distance, but then you have to worry about the lifespan of the big star. I don't know if a proper balance between the two exists...

Re: [Space] What is the 'Gaia' type of garden worlds like? ('Habitability 9').
 

We're talking about the limited case of planets that orbit the center of mass of both stars. Putting a small, dim star between a brighter star and a planet maximizes its' effect on insolation.

It certainly complicates matters we'd probably rather have be simple so my "best case" scenario for circumbinary stars was a matched pair rather than a dissimilar pair.

The complexity issue is the core of my disbelief of a unique and positive role for circumbinary stars. You can get more insolation from a single star just by assuming a different orbit and still have less variability.

Re: [Space] What is the 'Gaia' type of garden worlds like? ('Habitability 9').
 

Earth itself gets extremely variable insolation. Sometimes it drops to as low as 0 in locations undergoing night-time.

Jokes aside- the effect I was looking for with a circumbinary planet was basically just shortening the average nightcycle because one sun would set up to an hour after the other, then the first would rise an hour earlier. This would extend the daylight hours and give more crop-growing sunlight. But- you could probably also get the same extra amount of sunlight by finding a planet closer to its sun or with a brighter sun. While most of the posts had been about a Gaia planet's own morphology, I was wondering if its stellar environment should also be considered.

I found a candidate for this kind of case. Gamma Ursae Majoris, a large, hot AO class star, was recently found to have a K2 companion at 11AU. This paper analyses the habitable zones of circumstellar planets when affected by a distant binary partner, and Gamma Ursa Major is referred to as HIP 58001. The A0 is 65 times brighter than our sun, and the K2 is 0.397 times. The habitable zone plots (on p3107) show you could have a planet between 0.7 and 1.2 AU from the K2.

If a putative Gaia world was at 1 AU, the A0 would vary between 45% and 65% of the brightness of our sun throughout the planet's year, as it moved between 10 and 12 AU distance. Combined with the K2's brightness, insolation would vary between 85% and 105% of the Earth's throughout its year.

But, the interesting bit is that for almost half the year, the Gaia would get no night-time, as it would be passing between its close dwarf and distant hot giant. Crops would get a peak 24 hours a day growing season... but at 1/2 to 2/3rds the sunlight at any one time, I guess. Actually, working through it, I don't see this as giving a huge boost to crop output, unfortunately.

We could substitute in hotter stars in the same situation to help make up for the shortfall, but then it reduces the size of the habitable zone because the planet would overheat.

Re: [Space] What is the 'Gaia' type of garden worlds like? ('Habitability 9').
 

Anyone analyzing habitability of a binary containing an A0 star has to be looking for a capture situation where that A0 gains a smaller companion that's much older than itself. A A0 spends far too short a time on the Main Sequence for the evolution of Earth-like worlds. The biggest star that might live long enough is something like an F8.

It's hard to say how rare capture situations might be.

Re: [Space] What is the 'Gaia' type of garden worlds like? ('Habitability 9').
 

Name literally any other natural environmental aspect of earth that can be made harsher by a full 25% that somehow makes human lives better?
A few experiments with much different and much smaller chickens doesn't even come close to saying humans living in high gravities would somehow do better.
Just not buying it as anything realistic. But with all these extraterrestrial hypotheticals, most such suggestions will triggers someone's disbelief.

Re: [Space] What is the 'Gaia' type of garden worlds like? ('Habitability 9').
 

Sounds even more unlikely for planets of either star to survive such a stellar capture. The Late Heavy Bombardment would have nothing on that time period, I'd imagine.

Re: [Space] What is the 'Gaia' type of garden worlds like? ('Habitability 9').
 

Also, if not a capture situation, the system would be too young for life to begin around the K2 before the A0 began to expand into a red super-giant.

Re: [Space] What is the 'Gaia' type of garden worlds like? ('Habitability 9').
 

Switzerland.

Re: [Space] What is the 'Gaia' type of garden worlds like? ('Habitability 9').
 

If you're looking for maximum human population effectiveness, maybe a 'Gaia' world is a multi-level ecumenopolis?