[meteorite-list] Volunteer 'Disk Detectives' Classify Possible Planetary Habitats

[Ron Baalke]

http://www.jpl.nasa.gov/news/news.php?feature=4430

Volunteer 'Disk Detectives' Classify Possible Planetary Habitats
Jet Propulsion Laboratory
January 6, 2015

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."

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 Cernohous, 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).

JPL manages the NEOWISE mission for NASA's Science Mission Directorate 
in Washington. The Space Dynamics Laboratory in Logan, Utah, built the 
science instrument. Ball Aerospace & Technologies Corp. of Boulder, Colo., 
built the spacecraft. Science operations and data processing take place 
at the Infrared Processing and Analysis Center at the California Institute 
of Technology in Pasadena. Caltech manages JPL for NASA.

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.

More information about WISE is online at:

http://www.nasa.gov/wise


Media Contact

Written by Francis Reddy
Goddard Space Flight Center, Greenbelt, Md. 

Whitney Clavin 818-354-4673
Jet Propulsion Laboratory, Pasadena, Calif.
whitney.clavin at jpl.nasa.gov 

2015-004