Ras Algethi (ArabicRasalgethi from Ra`s al-Jathi a Head of the kneeling one) (α 1 Herculis | 64 Herculis) is a double star system with a primary massive red giantstar and a closer companion.
Physical and other characteristics
Ras Algheti is the 4th largest star known to us, circa 720 times greater than the Sun.