Norma Arm

The Norma Arm is a minor spiral arm of the Milky Way extending from and around its central hub region. The inner portion of the Arm is called Norma Arm in narrow meaning. The outer part of it is identified either with Cygnus Arm, which lies outside the Perseus Arm, or Outer Arm, which is located further away from the center of the Galaxy than Cygnus Arm. Norma Arm has a radius of 15.5 ± 2.8 kpc. It is named for the Norma constellation, through which the Arm as seen from Earth passes.