Citizen science project discovers new brown dwarf

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. Credit: NASA/WISE

One night three months ago, Rosa Castro finished her dinner,
opened her laptop, and uncovered a novel object that was
neither planet nor star. Therapist by day and amateur
astronomer by night, Castro joined the NASA-funded Backyard
Worlds: Planet 9 citizen science project when it began in
February—not knowing she would become one of four volunteers
to help identify the project’s first brown dwarf, formally
known as WISEA J110125.95+540052.8.

After devoting hours to skimming online, publicly available
“flipbooks” containing time-lapse images, she spotted a moving
object unlike any other. The search process involves fixating
on countless colorful dots, she explained. When an object is
different, it simply stands out. Castro, who describes herself
as extremely detail oriented, has contributed nearly 100
classifications to this specific project.

A paper about the new brown dwarf was published on May 24 in
The Astrophysical Journal Letters. Four are co-authors of the paper,
including Castro. Since then, Backyard Worlds: Planet 9 has
identified roughly 117 additional brown dwarf candidates.

The collaboration was inspired by the recently proposed ninth
planet, possibly orbiting at the fringes of our solar system
beyond Pluto.

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

It’s been roughly two decades since researchers first
discovered brown dwarfs, and the scientific community opened
its eyes to this new class of objects between stars and
planets. Although they are as common as stars and form in much
the same way, brown dwarfs lack the mass necessary to sustain
nuclear fusion reactions. They therefore do not have the energy
to maintain their luminosity, so they slowly cool over the
course of their lifetimes. Their low temperatures also render
them intrinsically dim.

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. Credit: NASA’s Goddard Space Flight
Center

For years, Kuchner has been fascinated by infrared images of
the entire sky captured by NASA’s Wide-field Infrared Survey
Explorer (WISE), launched in 2009. The space telescope is
specially designed to observe cold objects emitting light at
long wavelengths—objects like brown dwarfs. With its initial
mission complete, WISE was deactivated in 2011. It was then
reactivated in 2013 as NEOWISE, a new mission funded by the NEO
Observations Program with a different goal: to search for
potentially hazardous near-Earth objects (NEOs).

Previously, Kuchner had focused on stationary objects seen by
WISE. But the Backyard Worlds: Planet 9 project shows the WISE
and NEOWISE data in a way custom-tailored for finding
fast-moving objects. His team layers many images of the same
location to create a single, comprehensive snapshot. These are
then combined with several similarly “co-added” pictures to
form flipbooks that show motion over time.

Anyone with internet access can scour these flipbooks and click
on anomalies. If they would like to call the science team’s
attention to an object they found, they can submit a report to
the researchers or share their insights on a public forum.
Kuchner and his colleagues then follow up the best candidates
using ground-based telescopes to glean more information.

According to Backyard Worlds: Planet 9 citizen scientist Dan
Caselden, participants are free to dig as deep into the results
as they choose. A security researcher by trade, Caselden
developed a series of tools allowing fellow participants to
streamline their searches and visualize their results, as well
as aggregate various user statistics. He also helped identify
several of the additional brown dwarf candidates while the
first discovery was being confirmed.

Kuchner and his co-author, Adam Schneider of Arizona State
University, Tempe, agree WISEA J110125.95+540052.8 is an
exciting discovery for several reasons. “What’s special about
this —besides the way it was discovered—is that
it’s unusually faint,” Schneider said. “That means our citizen
scientists are probing much deeper than anyone has before.”

While computers efficiently sift through deluges of data, they
can also get lost in details that human eyes and brains easily
disregard as irrelevant.

This illustration shows a close-up view of a Y dwarf.
Objects like this, drifting just beyond our solar system, have
been imaged by NASA’s Wide-field Infrared Survey Explorer and
could be discovered by Backyard Worlds: Planet 9. Credit:
NASA/JPL-Caltech

However, mining this information is extremely arduous for a
single scientist or even a small group of researchers. That’s
precisely why collaborating with an enthusiastic public is so
effective—many eyes catch details that one pair alone could
miss.

While Kuchner is delighted by this early discovery, his
ultimate goal for Backyard Worlds: Planet 9 is to find the
smallest and coldest , called Y dwarfs. Some of these Y
dwarfs many even be lurking closer to us than Proxima Centauri,
the nearest star to the sun.

Their low temperatures make Y dwarfs extremely dim, according
to Adam Burgasser at the University of California San Diego.
“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,” he said. “Anytime you get a diverse set of people
looking at the data, they’ll bring unique perspectives that can
lead to unexpected discoveries.”

Kuchner anticipates the Backyard Worlds effort will continue
for several more years—allowing more volunteers like Caselden
and Castro to contribute.

As Castro put it: “I am not a professional. I’m just an amateur
astronomer appreciating the night sky. 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 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.

Explore further:

Citizen scientists uncover a cold new world near sun

More information: Marc J. Kuchner et al. The First Brown
Dwarf Discovered by the Backyard Worlds: Planet 9 Citizen
Science Project, The Astrophysical Journal (2017).
DOI: 10.3847/2041-8213/aa7200