Spaceflight Insider

Brown dwarf discovered with the help of citizen scientists

Star scale

This illustration shows the average brown dwarf is much smaller than our Sun and low-mass stars and only slightly larger than the planet Jupiter. Image & Caption Credit: NASA’s Goddard Space Flight Center

Sometimes in science, when you search for one thing, you end up finding something completely different. Such is the case with the search for the thus far elusive Planet Nine and the citizen scientists who ended up finding a brown dwarf instead.

Backyard Worlds: Planet 9 is a NASA-funded project sponsored by Zooniverse, and is the group under whose auspices the discovery was made just weeks after its official launch on February 15, 2017. The launch date, which also happened to coincide with the 87th anniversary of the discovery of Pluto, was a tip of the hat to the methodology that is being used to look for the hypothesized planet along with other dim rogue worlds in the far distant outer reaches of the Solar System and beyond.

Brown dwarf WISEA J110125.95+540052.8

The newly discovered brown dwarf WISEA J110125.95+540052.8 appears as a moving dot (indicated by the circle) in this animated flipbook from the Backyard Worlds: Planet 9 citizen science project. Image & Caption Credit: NASA / WISE

The search for Planet Nine, also called Planet X by some, has led to several new discoveries, including this brown dwarf designated WISEA 1101+5400.

“We realized we could do a much better job identifying Planet 9 if we opened the search to the public,” said Marc Kuchner, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and lead researcher for the Backyard Worlds project. “Along the way, we’re hoping to find thousands of interesting brown dwarfs.”

WISEA 1101+5400 (full name WISEA J110125.95+540052.8) was found with the critical assistance of four citizen scientists, one of whom is Rosa Castro, a therapist, who is credited with nearly 100 classifications as a part of this project.

Backyard Worlds, along with the majority of the other projects under the umbrella of Zooniverse, relies heavily on citizen scientists to sort through huge volumes of data for things that stand out to them. In this case, the project provides participant individuals with “flipbooks” – animated collections of time-lapsed images of the same part of space – to review, noting any visible changes in the position or brightness of the pixels within the series of images.

The flipbooks are a collection of the data that was gathered by the Wide-Field Infrared Survey Explorer (WISE) which was launched into space on December 14, 2009.

Originally designed to observe cold objects, as well as those that emit light in the infrared portion of the spectrum (long wavelengths) such as brown dwarfs, WISE was deactivated in 2011 after depleting its source of frozen hydrogen that was needed to cool the sensors, and then reactivated in 2013 as NEOWISE to search for near-Earth objects, or NEOs, which tend to be cold, dark objects easier to locate in the infrared spectrum.

The data that the WISE and NEOWISE missions gathered of the entire sky provides one of the best chances of locating the enigmatic Planet 9 because it may already have been caught in those images. It takes human eyes to be able to look through the noise filled images and be able to recognize these objects, though.

There are a vast number of images, more images than a small team of researchers alone could process in a lifetime, which is why the Backyard Worlds project was created and opened up to the public. What started out as a small group of individuals has grown significantly in the five months it has been in operation. Currently, there are several hundred (or more) citizen scientists looking through the flipbooks for additional objects.

So, what’s the deal with WISEA 1101+5400? WISEA1101+5400 isn’t exactly local with a location approximately 34 parsecs (111 light-years) from Earth in the constellation Ursa Major. The object is a brown dwarf classified as a spectral T5.5, meaning that its size and mass are too low to sustain fusion as a star and that its temperature runs between 900–1,500 K (630–1,230 °C / 1,160–2,240 °F).

T-class brown dwarf

Artist’s rendition of a T-class brown dwarf. Image Credit: NASA/JPL-Caltech

Researchers took images of the spectra (light) from the object and found that it was nearly identical to other T dwarfs, containing specific amounts of water, methane, iron hydride, potassium, and molecular hydrogen. If the object were cooler or hotter, the amounts and variety of these molecules in the spectral analysis would be different.

WISEA-1101+5400 spectrum

The spectrum of WISEA 1101+5400 in black with another T5.5 brown dwarf in red. Image Credit: Kuchner et al.

In fact, WISEA 1101+5400 is pretty average as far as T dwarfs go. What isn’t average is who and how it was discovered. It’s unlikely that Rosa Castro, Dan Caselden, or the two other citizen scientists involved with the discovery, had set out to find this cold distant object, but find it they did, and just six days after the start of the project.

Even with WISEA 1101+5400 averageness, the researchers are excited. Kuchner hopes that with enough time and interest, they will be able to locate super small, super-cold brown dwarfs called Y-dwarfs, some of which may be lurking far closer to us than we realize.

“They’re so faint that it takes quite a bit of work to pull them from the images, that’s where Kuchner’s project will help immensely,” said Adam Burgasser at the University of California San Diego. “Anytime you get a diverse set of people looking at the data, they’ll bring unique perspectives that can lead to unexpected discoveries.”

It’s interesting to note that this isn’t the only discovery that Backyard Worlds has made. There are currently 117 additional brown dwarf candidates being vetted all from this citizen science driven project, and Kuchner expects that the Backyard Worlds effort will continue for several years to come allowing more volunteers to get involved.

“I am not a professional. I’m just an amateur astronomer appreciating the night sky,” said Rosa Castro. “If I see something odd, I’ll admire and enjoy it.”

Backyard Worlds: Planet 9 is a collaboration between NASA, UC Berkeley, the American Museum of Natural History in New York, Arizona State University, the Space Telescope Science Institute in Baltimore, and Zooniverse – a collaboration of scientists, software developers, and educators who collectively develop and manage citizen science projects on the Internet.

NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, manages the NEOWISE mission for NASA’s Planetary Defense Coordination Office within the Science Mission Directorate in Washington. The Space Dynamics Laboratory in Logan, Utah, built the science instrument. Ball Aerospace & Technologies Corp. of Boulder, Colorado, built the spacecraft. Science operations and data processing take place at the Infrared Processing and Analysis Center at Caltech in Pasadena. Caltech manages JPL for NASA.

For more information, visit Backyard Worlds: Planet 9 and NASA’s WISE mission.



A native of the Greater Los Angeles area, Ocean McIntyre's writing is focused primarily on science (STEM and STEAM) education and public outreach. McIntyre is a NASA/JPL Solar System Ambassador as well as holding memberships with The Planetary Society, Los Angeles Astronomical Society, and is a founding member of McIntyre is currently studying astrophysics and planetary science with additional interests in astrobiology, cosmology and directed energy propulsion technology. With SpaceFlight Insider seeking to expand the amount of science articles it produces, McIntyre was a welcomed addition to our growing team.

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