ESO / Igor Chekalin
This image of the Orion Nebula was captured using the Wide Field Imager camera on the MPG/ESO 2.2-meter telescope at the La Silla Observatory in Chile. This image is a composite of several exposures taken through five different filters. The exposure times were about 52 minutes through each filter.
The Orion Nebula is one of the best-known star-forming regions in our celestial neighborhood, but astronomers can still find some "hidden treasures" if they just look at the nebula in a different light.
Case in point: this ethereal picture of the Orion Nebula, featured today by the European Southern Observatory in Chile. The image is based on data from the MPG/ESO 2.2-meter telescope at the La Silla Observatory in Chile, and submitted by Russia's Igor Chekalin for the ESO's Hidden Treasures astrophotography competition. This particular image took seventh place. Another one of Chekalin's entries, showing the M78 reflection nebula in Orion, won first prize (and earned Chekalin a trip to Chile).
The Orion Nebula, also known as M42, is a huge complex of gas and dust where massive stars are constantly being squeezed into existence. It's about 1,350 light-years away, which is pretty close by astronomical standards. You've probably already figured out that the nebula is in the constellation Orion, which is at center stage in the night sky at this time of year.
The hidden treasures that Chekalin found were data sets from roughly 52-minute exposures taken in five different wavelengths. The rays of light that passed through a red filter and through a filter sensitive to glowing hydrogen gas are represented as red in this image. Light in the yellow-green part of the spectrum is shown here as green. The blue-filter image is reproduced as blue, and ultraviolet shows up as purple. The result is a beautiful picture that sheds new light on the nebula's gauzy structure.
For additional perspectives, check out this ESO vidcast from last year, which compares infrared and visible-light imagery of the Orion Nebula:
The infrared-vs.-visible view is a major focus for NASA researchers using the brand-new Stratospheric Observatory for Infrared Astronomy, or SOFIA. During last week's winter meeting of the American Astronomical Society in Seattle, the researchers in charge of SOFIA's airborne telescope showed off an infrared mosaic image of the Orion Nebula that was captured during their "Short Science 1" observing program in December.
Infrared-sensitive telescopes are particularly good at tracing the structures within dusty star-forming regions. Here's a comparison of the Hubble Space Telescope's visible-light view (left), ESO's near-infrared view (middle) and SOFIA's mid-infrared view (right):
These images show the Orion Nebula as seen by the Hubble Space Telescope in visible light (left), the European Southern Observatory in near-infrared wavelengths (middle) and the SOFIA airborne observatory in mid-infrared wavelengths (right). Credits for the visible-light image: NASA/ESA/HST/AURA/STScI/O'Dell & Wong. Near-infrared image: ESO/McCaughrean et al. Mid-infrared image: NASA/DLR/SOFIA/USRA/DSI/FORCAST Team.
The dense cloud of interstellar dust at upper left is completely opaque in visible light, partially transparent in the near-infrared and glowing with heat in the mid-infrared. Dust-shrouded stars can easily be seen shining at upper right in the mid-infrared, but they're less apparent in the near-infrared and completely hidden in visible light. In contrast, the hot stars of the Trapezium Cluster sparkle in visible light and near-infrared, but are barely visible in SOFIA's mid-infrared view.
For astronomers, this isn't just a game of hide-and-seek. Comparing different views, in different wavelengths, is how scientists figure out what's going on deep within distant nebulas and galaxies. The scientific insights gained through such comparisons are the true "hidden treasures" of the cosmos.
More wonders in multiple wavelengths:
- Telescopes do a triple take
- Hubble's new superpowers
- Scientists team up on telescopes
- 10 Hubble targets you can find too
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