Note: Single-source report; awaiting corroboration.
NASA's Backyard Worlds: Planet 9 citizen science project has doubled the number of known brown dwarfs, with volunteers discovering over 3,000 new objects in the past decade. Brown dwarfs are gas balls about the size of Jupiter but with less mass than stars, existing at a ratio of roughly one for every three or four stars near the Sun.
Despite their abundance, brown dwarfs are hard to detect due to their faint glow compared to stars. This expanded catalog now includes a wider variety of brown dwarf types, such as extreme T subdwarfs, ultra-cool objects, and at least one brown dwarf with aurorae.
The discoveries, detailed in a paper published in the Astronomical Journal and led by Adam Schneider of the U.S. Naval Observatory, were made by a network of about 200,000 volunteers. Of the 75 authors on the paper, 61 are volunteers—some of whom began as amateurs before pursuing careers in astronomy. Volunteers analyzed image data from NASA’s retired Wide-field Infrared Survey Explorer (WISE) and the Near-Earth-Object WISE Reactivation mission (NEOWISE-R) using the Zooniverse platform, identifying moving objects in images taken over 16 years.
Some volunteers also developed their own tools and software to support the search. The project continues to scan over 2 billion sources captured by WISE and NEOWISE-R and invites new participants to help find more brown dwarfs.