Mu Herculis

Though Mu Herculis appears as a single star in this image, it is in fact a multiple system consisting of pair of binaries. The bright central star is a yellow subgiant with a red dwarf in a very close orbit, and in combination these comprise the 'A' component (also known as Mu¹ Herculis or Mu Herculis Aab). Slightly to the southwest (though not separately distinguishable in this image) is a second pair of red dwarf stars, the BC component (also designated Mu² Herculis). Imagery provided by Aladin sky atlas