Two Solar System Puzzles Solved

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Two Solar System Puzzles Solved

Washington, D.C.— Comets and asteroids preserve the building blocks of our Solar System and should help explain its origin. But there are unsolved puzzles. For example, how did icy comets obtain particles that formed at high temperatures, and how did these refractory particles acquire rims with different compositions? Carnegie’s theoretical astrophysicist Alan Boss and cosmochemist Conel Alexander* are the first to model the trajectories of such particles in the unstable disk of gas and dust that formed the Solar System. They found that these refractory particles could have been processed in the hot inner disk, and then traveled out to the frigid outer regions to end up in icy comets. Their meandering trips back and forth could help explain the different compositions of their rims. The research is published in Earth and Planetary Science Letters.

The young Sun is thought to have experienced a series of outbursts caused by the rapid infall of disk gas onto the Sun. The leading mechanism for explaining such outbursts is a phase of disk instability. The researchers modeled the trajectories of several hundred centimeter-sized melilite mineral particles during a phase of disk instability. These particles are similar to calcium-aluminum-rich inclusions (or CAIs), the refractory particles often found in well-preserved meteorites, as well as the comet Wild 2.

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