The constellation of Orion showing the region shown in a new APEX image
Wide-field view of part of Orion in visible light
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This dramatic new image of cosmic clouds
in the constellation of Orion reveals what seems to be a fiery ribbon in
the sky. This orange glow represents faint light coming from grains of
cold interstellar dust, at wavelengths too long for human eyes to see.
It was observed by the ESO-operated Atacama Pathfinder Experiment (APEX)
in Chile.
Clouds of gas and interstellar dust are the raw materials from which
stars are made. But these tiny dust grains block our view of what lies
within and behind the clouds — at least at visible wavelengths — making
it difficult to observe the processes of star formation.
This is why astronomers need to use instruments that are able to see
at other wavelengths of light. At submillimetre wavelengths, rather than
blocking light, the dust grains shine due to their temperatures of a
few tens of degrees above absolute zero [1].
The APEX telescope with its submillimetre-wavelength camera LABOCA,
located at an altitude of 5000 metres above sea level on the Chajnantor
Plateau in the Chilean Andes, is the ideal tool for this kind of
observation.
This spectacular new picture shows just a part of a bigger complex
called the Orion Molecular Cloud, in the constellation of Orion (The
Hunter). A rich melting pot of bright nebulae, hot young stars and cold
dust clouds, this region is hundreds of light-years across and located
about 1350 light-years from us. The submillimetre-wavelength glow
arising from the cold dust clouds is seen in orange in this image and is
overlaid on a view of the region taken in the more familiar visible
light.
The large bright cloud in the upper right of the image is the
well-known Orion Nebula, also called Messier 42. It is readily visible
to the naked eye as the slightly fuzzy middle “star” in the sword of
Orion. The Orion Nebula is the brightest part of a huge stellar nursery
where new stars are being born, and is the closest site of massive star
formation to Earth.
The dust clouds form beautiful filaments, sheets, and bubbles as a
result of processes including gravitational collapse and the effects of
stellar winds. These winds are streams of gas ejected from the
atmospheres of stars, which are powerful enough to shape the surrounding
clouds into the convoluted forms seen here.
Astronomers have used these and other data from APEX along with
images from ESA’s Herschel Space Observatory, to search the region of
Orion for protostars — an early stage of star formation. They have so
far been able to identify 15 objects that appeared much brighter at
longer wavelengths than at shorter wavelengths. These newly discovered
rare objects are probably among the youngest protostars ever found,
bringing astronomers closer to witnessing the moment when a star begins
to form.
Notes
[1] Hotter objects give off most of
their radiation at shorter wavelengths and cooler ones at longer
wavelengths. As an example very hot stars (surface temperatures around
20 000 degrees Kelvin) look blue and cooler ones (surface temperatures
of around 3000 degrees Kelvin) look red. And a cloud of dust with a
temperature of only ten degrees Kelvin has its peak of emission at a
much longer wavelength — around 0.3 millimetres — in the part of the
spectrum where APEX is very sensitive.
More information
The research on protostars in this region is
described in the paper “A Herschel and APEX Census of the Reddest
Sources in Orion: Searching for the Youngest Protostars” by A. Stutz et
al., in the Astrophysical Journal.
The APEX observations used in this image were led by Thomas Stanke
(ESO), Tom Megeath (University of Toledo, USA), and Amelia Stutz (Max
Planck Institute for Astronomy, Heidelberg, Germany). APEX is a
collaboration between the Max Planck Institute for Radio Astronomy
(MPIfR), the Onsala Space Observatory (OSO) and ESO. Operation of APEX
at Chajnantor is entrusted to ESO.
ESO is the foremost intergovernmental astronomy organisation in
Europe and the world’s most productive ground-based astronomical
observatory by far. It is supported by 15 countries: Austria, Belgium,
Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy,
the Netherlands, Portugal, Spain, Sweden, Switzerland and the United
Kingdom. ESO carries out an ambitious programme focused on the design,
construction and operation of powerful ground-based observing facilities
enabling astronomers to make important scientific discoveries. ESO also
plays a leading role in promoting and organising cooperation in
astronomical research. ESO operates three unique world-class observing
sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO
operates the Very Large Telescope, the world’s most advanced
visible-light astronomical observatory and two survey telescopes. VISTA
works in the infrared and is the world’s largest survey telescope and
the VLT Survey Telescope is the largest telescope designed to
exclusively survey the skies in visible light. ESO is the European
partner of a revolutionary astronomical telescope ALMA, the largest
astronomical project in existence. ESO is currently planning the
39-metre European Extremely Large optical/near-infrared Telescope, the
E-ELT, which will become “the world’s biggest eye on the sky”.
Links
- Related press releases:
- Research paper
- Photos of APEX
- Photos taken by APEX
Contacts
Amelia StutzMax Planck Institute for Astronomy
Heidelberg, Germany
Tel: +49 6221 528 412
Email: stutz@mpia.de
Thomas Stanke
ESO
Garching bei München, Germany
Tel: +49 89 3200 6116
Email: tstanke@eso.org
Richard Hook
ESO Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
Email: rhook@eso.org
