Artist’s concept of the ancient impact in the HD 172555 system. A smaller object smashed into a young Earth-sized world about 200,000 years ago. The larger exoplanet lost its atmosphere as a result. It gives a new meaning to having the wind knocked out of you. Image via Mark A. Garlick/ MIT News.
Our early solar system was a chaotic and violent place, with rocky bodies colliding in big and small smashups. In fact, such collisions gradually formed the planets and moons we see today. On October 20, 2021, astronomers said they found evidence for how a young exoplanet lost its atmosphere in a giant impact thousands of years ago.
The peer-reviewed journal Nature published the findings of researchers from MIT, the National University of Ireland Galway, Cambridge University and other institutions on October 20, 2021.
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How an exoplanet lost its atmosphere
Notably, the evidence didn’t come from the planet itself, but from a ring of dust and gas orbiting the star HD 172555. These rings, or disks, are called circumstellar disks. ...