AC Herculis

AC Herculis, is an RV Tauri variable and spectroscopic binary star in the constellation of Hercules.

AC Her is an RVa star, meaning it is an RV Tauri variable whose maximum and minimum magnitudes do not slowly vary over hundreds of days.

[10] AC Her is also a binary star, its companion was detected with spectroscopy and long baseline interferometry.

Interferometric observations from the CHARA Array enabled its three dimensional orbit with a semimajor axis of 2.01 ± 0.01 mas, equivalent to 2.83 ± 0.08 au.

The two stars are also surrounded by a dusty disc filling the region between 34 and 200 astronomical units (AU).