Alcyone is a blue B7IIIe giant star. Burnham estimates the luminosity of Alcyone as about 1000 times that of the sun. The star is almost 20 times the diameter of the sun. Alcyone is the brightest star of the Pleiades.
The Pleiades is one of the nearest open clusters to the earth. The cluster probably contains a few hundred stars. The brightest stars of the cluster nine spectral type B giants, concentrated in an area about 7 ly in diameter. The most distant members of the cluster lie up to about 20 ly from the center.
The The Bright Star Catalog suggests that as many as 5 other stars may be associated with Alcyone in a multiple star system.