Large Magellanic Cloud Blows Superbright Superbubble
Way off in the Large Magellanic Cloud, some 160,000 light years from Earth, a huge superbubble has formed around a star cluster cataloged as NGC 1929.
Here new stars are being formed… Some of them are massive. Encasing this jewel-like assortment of stars is a nebula known as N44. As quiet as the scenery looks, it’s home to some serious stellar turmoil. What creates such beauty – yet harbors such power? Inside N44 massive stars are busy expelling intense radiation.
Pushing through their envelope at incredible speeds, the stars race through their evolutionary process and quickly go supernova. Now the stellar winds and shock waves emerge, chewing out huge portions in the surrounding gas. These emptying spaces are known as superbubbles.
In this image, X-rays from NASA’s Chandra X-ray Observatory (blue) show hot regions created by these winds and shocks, while infrared data from NASA’s Spitzer Space Telescope (red) outline where the dust and cooler gas are found. The optical light from the 2.2-m Max-Planck-ESO telescope (yellow) in Chile shows where ultraviolet radiation from hot, young stars is causing gas in the nebula to glow.
Despite this explanation, there is still a mystery here. Astrophysicists are puzzle that some superbubbles in the LMC, including N44, emit more X-ray energy than what they should. According to their models, researchers expect the massive stars to produce serious stellar winds and hot, X-ray emitting gases. According to the press release, a Chandra study published in 2011 showed that there are two extra sources of N44’s X-ray emission not included in these models: supernova shock waves striking the walls of the cavities, and hot material evaporating from the cavity walls.
However, the mystery hasn’t ended there. Chandra observations also gave no clue as to why there isn’t any evidence for an enhancement of elements heavier than hydrogen and helium hidden in the bubble walls. This rules out the possibility as a third explanation for the bright X-ray emission. “Only with long observations making full use of the capabilities of Chandra has it now become possible to distinguish between different sources of the X-rays produced by superbubbles.”
The Chandra study of N44 and another superbubble in the LMC was led by Anne Jaskot from the University of Michigan in Ann Arbor. The co-authors were Dave Strickland from Johns Hopkins University in Baltimore, MD, Sally Oey from University of Michigan, You-Hua Chu from University of Illinois and Guillermo Garcia-Segura from Instituto de Astronomia-UNAM in Ensenada, Mexico.
Original Story Source: Chandra News Release.
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