A NASA-sponsored website designed to crowdsource analysis of data
from the agency's Wide-field Infrared Survey Explorer (WISE) mission has
reached an impressive milestone. In less than a year, citizen
scientists using DiskDetective.org
have logged 1 million classifications of potential debris disks and
disks surrounding young stellar objects (YSO). This data will help
provide a crucial set of targets for future planet-hunting missions.
"This is absolutely mind-boggling," said Marc Kuchner, an
astrophysicist at NASA's Goddard Space Flight Center in Greenbelt,
Maryland, and the project's principal investigator. "We've already
broken new ground with the data, and we are hugely grateful to everyone
who has contributed to Disk Detective so far."
Volunteers using DiskDetective.org, a NASA-sponsored citizen science website to
find potential planetary nurseries, have made 1 million classifications
in less than a year. Goddard astrophysicist Marc Kuchner, the project's
principal investigator, explains how it works.Image Credit: NASA's Goddard Space Flight Center/S. Wiessinger. Download this video in HD formats from NASA Goddard's Scientific Visualization Studio
The
marked asymmetry of the debris disk around the star HD 181327 (shown
here in a Hubble image) suggests it may have formed as a result of the
collision of two small bodies. Disk Detective aims to discover many
other stellar disks using volunteer classifications of data from NASA's
WISE mission.Image Credit: NASA, ESA, G. Schneider (U. of Arizona), HST/GO 12228 Team
Combing through objects identified by WISE during its infrared survey of the entire sky, Disk Detective aims to find two types of developing planetary environments. The first, known as a YSO disk, typically is less than 5 million years old, contains large quantities of gas, and often is found in or near young star clusters. The second planetary habitat, known as a debris disk, tends to be older than 5 million years, holds little or no gas, and possesses belts of rocky or icy debris that resemble the asteroid and Kuiper belts found in our own solar system. Vega and Fomalhaut, two of the brightest stars in the sky, host debris disks.
Planets form and grow within disks of gas, dust and icy grains surrounding young stars. The particles absorb the star's light and reradiate it as heat, which makes the stars brighter at infrared wavelengths -- in this case, 22 microns -- than they would be without a disk.
Computer searches already have identified some objects seen by the WISE survey as potential dust-rich disks. But software can't distinguish them from other infrared-bright sources, such as galaxies, interstellar dust clouds and asteroids. There may be thousands of potential planetary systems in the WISE data, but the only way to know for sure is to inspect each source by eye.
Kuchner recognized that searching the WISE database for dusty disks was a perfect opportunity for crowdsourcing. He worked with NASA to team up with the Zooniverse, a collaboration of scientists, software developers and educators who collectively develop and manage citizen science projects on the Internet.
At DiskDetective.org, volunteers watch a 10-second "flip book" of a disk candidate shown at several different wavelengths as observed from three different telescopes, including WISE. They then click one or more buttons that best describe the object's appearance. Each classification helps astronomers decide which images may be contaminated by background galaxies, interstellar matter or image artifacts, and which may be real disks that should be studied in more detail.
In March 2014, just two months after Disk Detective launched, Kuchner
was amazed to find just how invested in the project some users had
become. Volunteers complained about seeing the same object over and
over. "We thought at first it was a bug in the system," Kuchner
explained, "but it turned out they were seeing repeats because they had
already classified every single object that was online at the time."
Some 28,000 visitors around the world have participated in the
project to date. What's more, volunteers have translated the site into
eight foreign languages, including Romanian, Mandarin and Bahasa, and
have produced their own video tutorials on using it.
Many of the project's most active volunteers are now joining in
science team discussions, and the researchers encourage all users who
have performed more than 300 classifications to contact them and take part.
One of these volunteers is Tadeáš Černohous, a postgraduate student
in geodesy and cartography at Brno University of Technology in the Czech
Republic. "I barely understood what scientists were looking for when I
started participating in Disk Detective, but over the past year I have
developed a basic sense of which stars are worthy of further
exploration," he said.
Alissa Bans, a postdoctoral fellow at Adler Planetarium in Chicago
and a member of the Disk Detective science team, recalls mentioning that
she was searching for candidate YSOs and presented examples of what
they might look like on Disk Detective. "In less than 24 hours," she
said, "Tadeáš had compiled a list of nearly 100 objects he thought could
be YSOs, and he even included notes on each one."
Speaking at a press conference at the American Astronomical Society
meeting in Seattle on Tuesday, Kuchner said the project has so far
netted 478 objects of interest, which the team is investigating with a
variety of ground-based telescopes in Arizona, California, New Mexico,
Argentina and Chile. "We now have at least 37 solid new disk candidates,
and we haven't even looked at all the new telescope data yet," he said.
Disk Detective currently includes about 278,000 WISE sources. The
team expects to wrap up the current project sometime in 2018, with a
total of about 3 million classifications and perhaps 1,000 disk
candidates. The researchers then plan to add an additional 140,000
targets to the site.
“We’ve come a long way, but there’s still lots and lots more work to
do -- so please drop by the site and do a little science with us!” added
Kuchner.
WISE has made infrared measurements of more than 745 million objects,
compiling the most comprehensive survey of the sky at mid-infrared
wavelengths currently available. With its primary mission complete, the
satellite was placed in hibernation in 2011. WISE was awoken in
September 2013, renamed the Near-Earth Object Wide-field Infrared Survey
Explorer (NEOWISE), and given a new mission to assist NASA's efforts in
identifying the population of potentially hazardous near-Earth objects
(NEOs).
Facilities involved in follow-up studies of objects found with Disk
Detective include Apache Point Observatory in Sunspot, New Mexico;
Palomar Observatory on Palomar Mountain, California; the Fred Lawrence
Whipple Observatory on Mount Hopkins, Arizona; the Leoncito Astronomical
Complex in El Leoncito National Park, Argentina; and Las Campanas Observatory, located in the Atacama Desert of Chile.
NASA is exploring our solar system and beyond to understand the
universe and our place in it. We seek to unravel the secrets of our
universe, its origins and evolution, and search for life among the
stars. Today’s announcement shares the discovery of our ever-changing
cosmos, and brings us closer to learning whether we are alone in the
universe.
- Download HD video from NASA Goddard's Scientific Visualization Studio
- Disk Detective website
- NASA-Sponsored 'Disk Detective' Lets Public Search for New Planetary Nurseries (01.30.2014)
- WISE mission
Francis Reddy
NASA's Goddard Space Flight Center, Greenbelt, Maryland
