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Barnard’s Loop

Barnard’s Arc, Sh2-276

Proper NamesBarnard's Loop, Barnard’s Arc
Messier NumberNone
NGC/IC NumberNone
Other DesignationsSh2-276
ConstellationOrion
Right Ascension (centre)5h 27m 30s
Declination (centre)-3° 58' 0"
DistanceHighly uncertain; between 500 and 1,400 light years
(160 to 440 parsecs)
MagnitudeApparent: +5.0
Absolute: -1.0 to -3.2, depending on distance
Mean DiameterApparent: 10°
Actual: 100 to 300 light years, depending on distance
Optimum VisibilityDecember / January
NotesThis 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.

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