"For decades, researchers thought they had the recipe for a solar system figured out. You put a star in the middle, scatter some rocky crumbs nearby for things like Earth, and let the gas giants like Jupiter and Saturn sweep up the leftovers in the cold, dark suburbs. It was neat, tidy, and, as it turns out, probably wrong — or at least very incomplete.
Exhibit A: HR 8799. This young star, just 130 light-years away, is
Ever since these planets were discovered nearly two decades ago, they’ve stood as a middle finger to our best theories of how planets are born. They were too big and too far away to exist by the rules.
The main problem with HR 8799 is called core accretion. This is the standard model for building a giant planet. Imagine a dusty disk around a young star. Inside this disk, ice and rock collide to form a solid core. Once that core gets to about ten times the mass of Earth, its gravity becomes so hungry that it starts inhaling gas from the surrounding disk. This is the accretion.
But the farther you go from the star, the less material you have to work with. So, you’d expect these planets which are farther from their star to be smaller. That’s why it’s so striking for planets to be huge and very far away from their star.
For starters, they found that all planets have a relatively similar chemistry. In other words, they formed in pretty much the same way. This likely means no collisions or extreme events.
They then found that the planets are metal-rich. In astronomy, anything heavier than hydrogen or helium is a “metal.”
ZME
Commentary/Response: Oops....
