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March 21, 2018

A French satellite that’s small enough to hold in your hand is looking for a big planet to make a move. The planet is expected to pass in front of its star in the next year or so, causing the star’s light to fade a bit. When the satellite sees that happen, it’ll notify a large telescope on the ground, which will study the event in detail.

Picsat consists of three cubes stacked together. Combined, they’re a foot tall, and weigh about eight pounds. One of the cubes holds a two-inch telescope.

The telescope can be small because its target, Beta Pictoris, is bigger and brighter than the Sun. And it’s just 63 light-years away, so it’s easily visible to the unaided eye.

Beta Pic is only about 25 million years old. And it’s surrounded by material for making planets — a wide disk of gas and dust. The disk already has given birth to at least one planet, which is much heavier than Jupiter, the giant of our own solar system.

Its orbit is aligned so that the planet is expected to pass in front of the star once every 18 years. If astronomers get a good look at such a passage, they can determine the planet’s size, telling them about its composition, and measure its atmosphere as starlight filters through it.

So Picsat will keep a constant eye on Beta Pic. It’ll also measure smaller drops in the star’s light as comets and asteroids pass in front of it. That will tell us more about how planetary systems form — big science from a small satellite.


Script by Damond Benningfield

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