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Volunteers helped astronomers find 3006 new dim objects near the Sun.
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There are faint points in the sky that slowly crawl among the stars. They are cooler than embers in a fireplace and smaller than the Sun: these are brown dwarfs. There are so many of them that astronomers can't keep up with reviewing all the images. That's when volunteers stepped in: ordinary people examined pictures from the telescope and flagged moving objects.
The Backyard Worlds: Planet 9 project collected 3006 new such bodies. Most are L dwarfs (2 357 of them), the rest are T dwarfs (649 of them). For each one, they measured how fast it moves across the sky and estimated its distance. Some turned out to be pairs: two dwarfs orbiting a common center of gravity, like dancers holding hands.
Brown dwarfs are neither stars nor planets. They are born like stars, from a collapsing cloud of gas, but they don't gather enough mass to ignite nuclear fusion in their cores. So they spend their lives cooling off, like a cup of tea left on the table.
Now astronomers have twice as many samples to study. They can use them to understand how often such objects form, what they are like inside, and whether they have planets. Volunteers sitting at their computers helped map the Sun's immediate neighborhood.
