Citizen Scientists Comb Images To Find An 'Overexcited Planet'

Professional astronomers have been turning to the public for help with their research. So far, these "citizen scientists" have helped characterize distant galaxies and discovered gravitation lenses.

Now you can add finding brown dwarfs to the list. An article just published in Astrophysical Journal Letters describes a brown dwarf discovered with the help of four volunteers through an online crowdsourced search.

The project is called Backyard Worlds: Planet 9. When NPR reported on it in February, the focus was on finding the planet that astronomers predict exists at the farthest reaches of the solar system.

But from the start, a second goal was to find brown dwarfs in the sun's celestial neighborhood — within about 300 light-years.

Brown dwarfs are curious objects. Their existence was predicted at least 50 years ago, but it wasn't until 1995 that astronomers had proof they exist.

"They're sometimes called failed stars," says astronomer and educator Jackie Faherty of the American Museum of Natural History. "But I don't like using the word 'failure' in the title, so sometimes I call them overexcited planets."

Brown dwarfs are more massive than planets but not quite massive enough to kick off the sustained nuclear fusion reaction that would turn them into true stars.

They do, however, give off some light, mostly at infrared wavelengths. NASA's Wide-field Infrared Survey Explorer, or WISE, space telescope is designed to look for objects that emit infrared light.

Faherty and some colleagues wondered whether they could use the millions of images taken over the years by that telescope to search for brown dwarfs.

Objects relatively close to the sun can move over time against a background of stationary stars.

And it turns out that the human eye is very good at spotting things that move against a crowded background.

Volunteers with Backyard Worlds get a kind of flipbook on their computer of four images of the same patch of sky, taken over a period of years.

The volunteer's job is to look for something moving in the images.

Just a few weeks after the project started earlier this year, four people found something.

"They saw a tiny speck of light jump," says Faherty. "It's just a speck of a jump, and that jump indicated to them that they found something that was moving near the sun."

They didn't know what they had found. All they knew was that it was dim and it was moving.

To figure out what it was, Faherty asked for time on a telescope that NASA runs in Hawaii that can also see infrared light.

"I got the telescope time at one o'clock in the morning," she says.

It wasn't easy to find the object because it is so faint. She says she worked with a furious intensity.

"I was like a telescope ninja trying to get this thing," says Faherty.

But she got it and recorded enough of its light to confirm it was indeed a brown dwarf.

Rosa Castro is one of the volunteers who found the moving object that turned out to be a brown dwarf. "I've always enjoyed astronomy, but life has a funny way of distracting you so I never really kept up with it," she says.

Castro says you don't have to know a lot about astronomy to join the hunt.

"I will be very honest with you," says Castro. "I didn't know what a brown dwarf was until this project. So this project became both a curiosity adventure for me and a learning process as well."

Faherty says 36,000 people have signed up to search for other interesting objects in the Backyard Worlds project and already have identified a couple dozen new objects worth checking out.

More volunteers are welcome.

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