Alcyone (Eta Tauri)
Alycone is actually a multiple star system. The primary, Alcyone A, is an eclipsing binary, consisting of two giant B stars with a separation of about 0.031 arc-seconds (roughly the distance of Jupiter from the Sun). The high rotational speed of Alcyone A – over 200 km/s (more than 100 times faster than the Sun) – has caused gas to spin from its equator into a surrounding light-emitting disk. This makes Alcyone A a Be star but with a disk thicker than usual.
The binary Alcyone A is orbited by three companions. Alcyone B and Alcyone C are both 8th magnitude white, main sequence A stars and are separated from A by 117 and 181 arcseconds, respectively. Alcyone C is a Delta Scuti star whose brightness varies from magnitude +8.25 to +8.30 with a period of 1.13 hours. Alcyone D is a yellow-white main sequence F star, with an apparent magnitude of +8.7, separated by 191 arcseconds from the primary.
Related category• NOTABLE STARS
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