AM Herculis is a binary variable star located in the constellation Hercules.

AM Herculis was first cataloged in 1923 by Max Wolf and was listed at the time as Veränderlicher 28.1923, which is now AN 28.1923 in the General Catalogue of Variable Stars.

[7] In 1976, the astronomer S. Tapia discovered that light from the star is both linearly and circularly polarized, showing that there was a strong magnetic field surrounding the system and revealing that the system was more complex than previously thought.

The accretion rate is unstable, at times decreasing dramatically and reducing the brightness of the whole system.

There are also periodic variations thought to be caused by the appearance and eclipse of the accreting regions during rotation of the white dwarf.