Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Eta Capricorni is a binary star in the constellation Capricornus. It also has the traditional star name Arm. It is approximately 158 light years from Earth. The primary component, Capricorni A, is a white A-type main sequence dwarf with an apparent magnitude of +4.82. Its companion, Capricorni B, has an apparent magnitude of +6.5 and is located 0.34 arcseconds from the primary. Sometimes, this star is called by the name Armus.