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. Previously thought to be 13,000 light-years away, it is now thought to lie 6,400 light years from the Solar System.
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 10.7 kiloparsecs, is located between the minor Cygnus and Carina–Sagittarius Arms. It is named after the Perseus constellation in the direction of which it is seen from Earth.
The Perseus Spiral arm contains a number of Messier objects:
- The Crab Nebula (M1)
- Open Cluster M36
- Open Cluster M37
- Open Cluster M38
- Open Cluster M52
- Open Cluster M103.
- Churchwell, Ed; Babler, Brian L.; Meade, Marlin A. (2009). "The Spitzer/GLIMPSE Surveys: A New View of the Milky Way" (pdf). Publications of the Astronomical Society of the Pacific. 121: 213–230. Bibcode:2009PASP..121..213C. doi:10.1086/597811.
- McKee, Maggie (8 December 2005). "Spiral arm of Milky Way looms closer than thought". New Scientist. Reed Business Information Ltd. Retrieved 31 October 2013.