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Seeing the Past

March 1, 2015

The stars can be like a time machine — they let us see what our own solar system was like when it was young. These snapshots in time are showing that many planetary systems may evolve in the same way as our own.

One especially early snapshot is the system known as HD 95086. It’s only around 15 million years old, compared to four-and-a-half billion years for the solar system.

The star is a bit bigger, brighter, and heavier than the Sun. A big disk of warm dust orbits close to the star, while an even bigger disk of cold dust orbits farther out. A jumbo planet inhabits the gap between the disks, and astronomers expect to find more.

The layout is similar to that of our solar system, which has a band of warm material close to the Sun — the asteroid belt — then a zone of giant planets, and finally a zone of cold debris beyond the planets.

A slightly older system shows a similar structure.

HR 8799 is roughly 30 million years old. The star is similar to the one in HD 95086. And it also has warm and cold dust sandwiching a realm of giant planets. Four planets have been seen so far, and all of them are more impressive than Jupiter, the giant of the solar system.

No one has found small planets like Earth in either system. But there’s plenty of room for them, because both systems are like scaled-up versions of our own. So there may be more to see as we get better snapshots of these young planetary systems.


Script by Damond Benningfield, Copyright 2015

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