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This "comet factory" reveals first secrets of planetary formation

Illustration for article titled This comet factory reveals first secrets of planetary formation

Planets have to start out somewhere, and the leading theory is that they begin as dust particles clumping together to form larger and larger building blocks, before finally emerging eons later as full-blown planets. But the exact physics that would allow such clumps to form has long been frustratingly unclear.


That's why new research of Oph-IRS 148, a star located some 400 light-years away in the constellation of Ophiuchus, is so exciting to astronomers — that's an artist's impression of the system up top. Using the ALMA telescope at the European Southern Observatory, astronomers have discovered what's known as a dust trap, a safe haven for particles to collide and combine without being in constant danger of falling into their parent star. In this case, a vortex in a disc of gas surrounding the star creates a high-pressure region in which the dust particles can merge together without losing orbit and plummeting toward the star.

This particular dust trap is unlikely to form planets — indeed, it's probable that the gaseous disc is connected to a hidden planet or possibly a companion star hidden from our view behind all the dust, so this particular solar system probably won't unlock all the deepest mysteries of planetary formation. But it does at least help explain just how dust particles could begin the process of forming vastly larger bodies without obliterating each other or getting vaporized by their star. Lead author Nienke van der Marel of the Netherlands's Leiden Observatory explains further:

“At first the shape of the dust in the image came as a complete surprise to us,” says van der Marel. “Instead of the ring we had expected to see, we found a very clear cashew-nut shape! We had to convince ourselves that this feature was real, but the strong signal and sharpness of the ALMA observations left no doubt about the structure. Then we realised what we had found. It’s likely that we are looking at a kind of comet factory as the conditions are right for the particles to grow from millimetre to comet size. The dust is not likely to form full-sized planets at this distance from the star. But in the near future ALMA will be able to observe dust traps closer to their parent stars, where the same mechanisms are at work. Such dust traps really would be the cradles for new-born planets.”


For more, check out the ESO website.

Image credit: ESO/L. Calçada.

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