Rasalgethi

Rasalgethi

(ras-al-jee -th'ee) (α Her) A visual binary in the constellation Hercules. The primary (A) is a red supergiant that varies irregularly in magnitude from 2.7 to 4.0, the 5th-magnitude yellow giant companion (B) appearing green by contrast. B is a spectroscopic binary, period 51.6 days. Spectral type: M5 I (A), G5 III + F2 (B); distance: 193 pc.