ESA spacecraft finds first oxygen gas molecules in space
Scientists have detected oxygen molecules in the star-forming region of
Orion. Researchers believe frozen dust particles consisting of oxygen
atoms evaporated in the heat of budding stars to form molecules.
In a new scientific paper published on Monday, the European Space
Agency's (ESA) Herschel spacecraft has discovered oxygen molecules in
space. The findings were published in the August 1 edition of
Astrophysical Journal.
While oxygen in its atomic form exists in water and carbon monoxide -
and according to researchers is therefore the third most abundant
element in the universe - ESA's Herschel mission has discovered the
first molecular instance of oxygen space. That is, two oxygen molecules
bound together to form the dioxygen (O2) molecule.
The oxygen molecules were discovered in the Orion star-forming
region. However, they are few in number. The scientists used three
infrared frequencies emitted by Herschel's far-infrared instrument and
found one oxygen molecule for every million hydrogen molecules within
gas and dust surrounding Orion's forming stars.
The scientists had decided to search Orion based on the theory that
heat from the constellation's forming stars would evaporate ice from
tiny dust grains to form oxygen molecules.
The largest single mirror ever built for a space telescope is aboard
the Herschel spacecraft, which collects "long-wavelength radiation from
some of the coldest and most distant objects in the universe," according
to the ESA.
 Bérengère Parise and her research team recently found hydrogen peroxide in the Rho Ophiuchi star formation 'Hiding' oxygen
According to Göran Pilbratt, a Netherlands-based ESA scientist on the
Herschel project, the scientists hope to find out where else in space
oxygen molecules may have formed.
"It will certainly be of considerable interest to establish
abundances of O2 in different environments to be able to understand what
is going on," he told Deutsche Welle in an e-mail. "Obviously
non-stationary processes must be at play. We already now know for a fact
a lot of the oxygen must exist in other forms than O2."
Pilbratt added that scientists long suspected oxygen molecules exist
in space, but have been baffled by their inability to find them. NASA's
Submillimeter Wave Astronomy Satellite and Sweden's Odin mission have
both searched so far, without any results.
"Stationary chemical models indicate that a lot of the oxygen in the
interstellar medium ought to exist in the form of O2, but previous
searches showed this not to be the case, providing upper limits two
orders of magnitude lower than the expected abundances," he said.
Other space scientists have been encouraged by this result. Bérengère
Parise, a French researcher based at the Max Planck Institute in Bonn,
whose team last month revealed the presence of hydrogen peroxide in
space, said that this new finding is a positive step.
"This discovery will allow astrochemists to refine their models and
better understand the chemical interplays between gas and dust particles
in interstellar clouds, as well as to understand how much material is
frozen out onto the surface of cold dust particles," she wrote in an
e-mail sent to Deutsche Welle.
"A measured abundance is always much more constraining for models
than an upper limit based on non-detections (as was available in the
past)," she added. "Star formation theories will also have to take into
account the observed abundance of oxygen in the computation of the
cooling rates."
NASA's California-based Paul Goldsmith, one of leaders of the
international team of investigators, said finding the oxygen molecules
opens the door to further questions.
"We didn't find large amounts of (oxygen molecules), and still don't
understand what is so special about the spots where we find it," he said
in a statement. "The Universe still holds many secrets."
Author: Gerhard Schneibel
Editor: Cyrus Farivar
http://www.dw-world.de/dw/article/0,,15291661,00.html
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