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Citizen scientists discover 100 cool worlds close to Earth

Citizen scientists have helped discover nearly 100 nearby cool worlds through a NASA project called Backyard Worlds.

The public identified 95 brown dwarfs within our cosmic neighborhood. Brown dwarfs are objects between stars and planets in size, being heavier than planets but lighter than stars. Some are even cool enough that they are comparable to Earth temperatures and could host water clouds.

Brown dwarfs don’t have enough mass for nuclear fusion of hydrogen to occur as it does in a regular star. But they do show some activity, with some believed to be fusing other elements. And despite their name, brown dwarfs don’t actually appear brown — instead, they would appear to be magenta or orangey-red if seen by the human eye.

Artist's rendering of white dwarf and brown dwarf
In this artist’s rendering, the small white orb represents the white dwarf (a remnant of a long-dead sunlike star), while the purple foreground object is the newly discovered brown dwarf companion, confirmed by NASA’s Spitzer Space Telescope. This faint brown dwarf was previously overlooked until being spotted by citizen scientists working with Backyard Worlds: Planet 9, a NASA-funded citizen science project. NOIRLab/NSF/AURA/P. Marenfeld/Acknowledgement: William Pendrill

These recently discovered objects are important for astronomers to understand the variety of brown dwarfs that exist. Researchers previously found the coldest-ever brown dwarf, WISE 0855, in 2014, which is a cool minus 10 degrees Fahrenheit. But this was a one-off finding that was considerably colder than any previously known brown dwarfs. With the new data, astronomers can see the links between this chilly object and other more common types of brown dwarf.

“These cool worlds offer the opportunity for new insights into the formation and atmospheres of planets beyond the solar system,” lead author Aaron Meisner from the National Science Foundation’s NOIRLab said in a statement. “This collection of cool brown dwarfs also allows us to accurately estimate the number of free-floating worlds roaming interstellar space near the sun.”

The Backyard Worlds project has made previous discoveries as well, with a network of 100,000 volunteers identifying 1,500 nearby cold worlds. The project is ongoing so if you want to participate you can join in at the Backyard Worlds website.

“It’s exciting these could be spotted first by a citizen scientist,” Meisner said. “The Backyard Worlds discoveries show that members of the public can play an important role in reshaping our scientific understanding of our solar neighborhood.”

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