Arcturus, Alpha Boötis (α Boo), is a red giant star located 36.7 light-years away in the northern constellation Boötes. With an apparent magnitude of -0.05, it is the brightest star in Boötes and the 4th brightest star in the sky. Arcturus is the brightest star in the northern celestial hemisphere, just outshining Vega and Capella. … Continue reading Arcturus