Fomalhaut is a young, nearby star. It’s only 25 light-years away and 440 million years old. As a celestial youngin’, it’s still surrounded by the cosmic junk left over from its formation. Hence, it’s surrounded by a wide debris disk full of raw material that might someday become planets. Still, for now, thanks to the Hubble Space Telescope, astronomers were able to witness large asteroids smashing into each other.
It sounds like the kind of thing we’d catch a glimpse of all the time, but we don’t. The asteroids smashing together near Fomalhaut? Astronomers only observe it twice over 20 years. That is considered a lot.
The latest event appeared as a mysterious point of light that wasn’t there before, then suddenly was. According to researchers, who published their findings in the journal Science, the most likely explanation is a collision between two big rocky objects roughly 60 kilometers across.
That’s just over 37 miles wide. That’s big enough to be considered the type of space object that can eventually “seed” a planet. Instead of growing into planets after eating all their fruit and veggies, they obliterated each other, producing a massive cloud of reflective dust… that can cause some problems for astronomers trying to observe.
Multiple Asteroids Just Slammed Into Each Other. Crazy, Right?
In the early 2000s, astronomers believed they had directly imaged a gas giant called Fomalhaut b, later nicknamed Dagon. By 2014, it had vanished. They concluded that Dagon was never a planet, but an expanding dust cloud from a previous asteroid collision.
That cloud is now officially rebranded as “circumstellar source 1,” while the new blob earns the equally romantic title of “cs2.”
Earlier, I told you that collisions like these are rare. So rare that researchers only observe 2/20 years. But they are, in fact, so rare that theories predicted collisions of this scale should happen maybe once every 100,000 years.
Fomalhaut delivered two in two decades. That suggests its outer disk is packed with hundreds of millions of sizable planetesimals, all on intersecting paths. It’s a cosmic demolition derby.
By watching how these dust clouds warp under starlight, astronomers can estimate the sizes, numbers, and compositions of objects in the disk. All of which is info that is almost impossible to obtain any other way. And since Fomalhaut is so close, it’s like we’re getting a front-row seat into the process that created our very own solar system.
And now we get to watch it happen in real time.
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