A new ScienceCast video examines "yellow balls" and their role in star formation.
Citizen scientists scanning images from NASA’s Spitzer Space
Telescope, an orbiting infra-red observatory, recently stumbled upon a
new class of curiosities that had gone largely unrecognized before:
yellow balls.
"The volunteers started chatting about the yellow balls they kept
seeing in the images of our galaxy, and this brought the features to our
attention," said Grace Wolf-Chase of the Adler Planetarium in Chicago.
The rounded features captured by the telescope, of course, are not
actually yellow, red, or green—they just appear that way in the
infrared, color-assigned images that the telescope sends to Earth. The
false colors provide a way to humans to talk about infrared wavelengths
of light their eyes cannot actually see.
"With prompting by the volunteers, we analyzed the yellow balls
and figured out that they are a new way to detect the early stages of
massive star formation," said Charles Kerton of Iowa State University,
Ames. "The simple question of 'Hmm, what's that?' led us to this
discovery."
A thorough analysis by the team led to the conclusion that the
yellow balls precede the green bubbles, representing a phase of star
formation that takes place before the bubbles form.
"Basically, if you wind the clock backwards from the bubbles, you get the yellow balls," said Kerton.
Researchers think the green bubble rims are made largely of organic molecules called polycyclic aromatic hydrocarbons (PAHs). PAHs are abundant in the dense molecular clouds where stars coalesce. Blasts of radiation and winds from newborn stars push these PAHs into a spherical shells that look like green bubbles in Spitzer's images. The red cores of the green bubbles are made of warm dust that has not yet been pushed away from the windy stars.
How do the yellow balls fit in?
"The yellow balls are a missing link," says Wolf-Chase. They
represent a transition "between very young embryonic stars buried in
dense, dusty clouds and slightly older, newborn stars blowing the
bubbles."
Essentially, the yellow balls mark places where the PAHs (green)
and the dust (red) have not yet separated. The superposition of green
and red makes yellow.
So far, the volunteers have identified more than 900 of these
compact, yellow features. The multitude gives researchers plenty of
chances to test their hypotheses and learn more about the way stars
form.
Meanwhile, citizen scientists continue to scan Spitzer's images
for new finds. Green bubbles. Red cores. Yellow balls. What's next?
You could be the one who makes the next big discovery. To get involved,
go to zooniverse.org and click on "The Milky Way Project."
Credits:
Author: Rachel Molina
Production editor: Dr. Tony Phillips
Credit: Science@NASA
Source: NASA/Science News
