Observed structure of the Milky Way's spiral arms.
The Perseus Arm is one of two major spiral arms of the Milky Way galaxy. The second major arm is called Scutum–Centaurus Arm. Perseus Arm begins from the distal end of the long Milky Way.
The Milky Way is a barred spiral galaxy with two major arms and a number of minor arms or spurs. The Perseus Spiral Arm, with a radius of approximately 10,700 parsecs, is located between the minor Cygnus and Carina–Sagittarius Arms. It is named after its proximity to the constellation Perseus.
There is speculation that the local spur known as the Orion–Cygnus Arm, which includes the Solar System and Earth and is located inside of Perseus Arm, is a branch of it, but this is unconfirmed.
The Perseus Spiral arm contains a number of Messier objects:
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