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NASA’s flying observatory peeks inside the iconic Swan Nebula

A composite image of the Omega, or Swan, Nebula
In this composite image of the Omega, or Swan, Nebula, SOFIA detected the blue areas near the center and the green areas. The white star field was detected by Spitzer. SOFIA’s view reveals evidence that parts of the nebula formed separately to create the swan-like shape seen today. NASA/SOFIA/Lim, De Buizer, & Radomski et al.; ESA/Herschel; NASA/JPL-Caltech

The Omega or Swan Nebula has been a target of astronomical research for 250 years, but astronomers have never been able to get a clear view of the inside of the structure until now, thanks to SOFIA, the Stratospheric Observatory for Infrared Astronomy.

SOFIA is NASA’s flying observatory, a collection of equipment aboard a modified Boeing 747SP jetliner aircraft that is able to fly high in the Earth’s atmosphere above the large majority of water vapor. This way, its sensitive instruments can detect infrared signals which are very weak or coming from a great distance away, when normally the vapor would interfere with these signals and make them impossible to spot.

Using instruments such as the German Receiver for Astronomy at Terahertz Frequencies (GREAT), SOFIA can detect infrared light which is given off by distant nebulae. By looking in the infrared wavelength, these instruments can peer through the clouds of dust which constitute nebulae, allowing the scientists to peek inside and see regions nearer to the center of the structure.

“The present-day nebula holds the secrets that reveal its past; we just need to be able to uncover them,” Wanggi Lim, a Universities Space Research Association scientist at the SOFIA Science Center at NASA’s Ames Research Center, said in a statement. “SOFIA lets us do this, so we can understand why the nebula looks the way it does today.”

The dust is not the only thing which makes seeing the stars at the center of the nebula difficult, however. The central region glows very brightly, so detectors on most telescopes are saturated, “similar to an overexposed photo,” according to NASA. SOFIA uses an instrument called FORCAST, or the Faint Object Infrared Camera for the SOFIA Telescope, which is able to see into the interior of the nebula and study the different regions within it, revealing that these regions formed in separate bursts of star birth across the nebula’s history.

“This is the most detailed view of the nebula we have ever had at these wavelengths,” Jim De Buizer, a senior scientist also at the SOFIA Science Center, said in the statement. “It’s the first time we can see some of its youngest, massive stars and start to truly understand how it evolved into the iconic nebula we see today.”

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