Apparent: 10° Actual: 100 to 300 light years, depending on distance
Optimum Visibility
December / January
Notes
This immense ring of matter is thought to have had its origins in a supernova explosion that took place in central Orion an estimated two million years ago. The expanding shockwave from this supernova created the ring-like structure of Barnard's Loop, and also expelled several members of its original multiple system to create runaway stars hurtling outward through the Galaxy.
A ring of matter that occupies the central region of Orion. It is thought to be caused by the active regions of Orion's Belt, and is immense in extent. Its dimensions are uncertain, but it is probably more than two hundred light years across, and almost surrounds the famous shape of the Hunter in the night sky. The Loop is too faint to be detected with the naked eye.
This image of the southern parts of Orion is filtered to highlight ionised hydrogen, making Barnard's Loop stand out distinctly as a wide 'C'-shaped structure. The two bright areas within the Loop represent the Orion Nebula (to the south) and the complex nebulosity around the starAlnitak in Orion's Belt (to the north). Imagery provided by Aladin sky atlas
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