A fourth magnitude star (V = 3.65), called also α Draconis,
in the constellation → Draco. Despite its designation
as Alpha (α), it is the seventh brightest star of the constellation.
Thuban is a → giant star of
→ spectral type A0 III lying 310
→ light-years away.
It has an faint → companion in an orbit with a 51 day period.
Thuban was the → pole star at about 2700 BC.
Other designations: HR 5291, HD 123299, and SAO 16273.
See also: Thuban, from Ar. Ath-thu’bân (الثعبان) “a large male snake;
basilisk.”