The Seven Sisters

Roughly 440 light years away from us, the Pleiades should be a familiar sight to any stargazer in the northern hemisphere. Residing in the constellation of Taurus, they’re one of the nearest open clusters to Earth. The brightest stars are hot blue stars, still only a youthful 100 million years old. At that age, you might think that planets could be forming around them. As a matter of fact, you might be right.

The star HD 23514 lies quite a bit south of the main cluster in this image (loosely 10 light years down from Merope), and it’s also a lot more Sun-like. Being a young star, it’s still surrounded by a lot of dust. Some of that dust is a little warmer than it should be, apparently, and astronomers take this to be evidence of planetessimals (baby planets) colliding with each other.

Objects roughly moon-sized to mars-sized are thought to form pretty quickly around a young star, within the first few hundred thousand years. After that, planets like Earth are thought to gradually build up over the next few hundred million years through a series of cataclysmic collisions. Any that manage to grow to 5-10 Earth masses will be massive enough to rapidly accrete hydrogen and helium, growing into gas giants.

It’s those collisions that could easily be creating this warm dust. Promisingly, it’s in a close Earth-like orbit around HD 23514 too. It could well be that, when we look at this star, we’re looking at a solar system in the making. Maybe one day, one of them will be another Earth. Or perhaps at least another Venus.

About Invader Xan

Molecular astrophysicist, usually found writing frenziedly, staring at the sky, or drinking mojitos.
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