3.99
Apparent Mag81.7
Distance (ly)A5V
Spectral Type8,000
Temperature (K)Alcor is the fainter companion to Mizar in the Big Dipper's handle. The ability to see Alcor beside Mizar was traditionally used as a test of eyesight.
Stellar Data
Apparent Magnitude3.99
Absolute Magnitude2
Distance81.7 light-years
Spectral TypeA5V
Temperature8,000 K
Luminosity10 L☉
Radius1.84 R☉
Mass1.8 M☉
Right Ascension13h 25m 13.5s
Declination+54° 59′ 16.7″
ConstellationUrsa Major
Notable Facts
- Seeing Alcor next to Mizar was an ancient test of visual acuity
- Alcor and Mizar together form a sextuple star system
- It is also known as the Horse and Rider with Mizar