BC, when it was less than 10 arcminutes away from the pole. It remained within one degree of celestial north for nearly 200 years afterwards, and even 900 years after its closest approach, was just 5° off the pole. Thuban was considered the pole star until about 1800 BC, when the much brighter Beta Ursae Minoris (Kochab) began to approach the pole as well. Having gradually drifted away from the pole over the last 4800 years, Thuban is now seen in the night sky at a declination of , RA . After moving nearly 47° off the pole by 10,000 AD, Thuban will gradually move back toward the north celestial pole. In 20,346 AD, it will again be the pole star, that year reaching a maximum declination of , at right ascension . Binary system Thuban is a single-lined spectroscopic binary. For a long time, only the primary star could be detected in the spectrum. The radial velocity variations of the stars can be measured and the pair have a somewhat eccentric orbit of 51.4 days. The secondary is a main-sequence star slightly cooler than the primary, with an A1 spectral class. The secondary star was detected in high spatial resolution observations using the Navy Precision Optical Interferometer. The secondary star is 1.8 magnitudes (at 700 nm) fainter than the primary star and was detected at separations ranging from 6.2 to 2.6 milliarcseconds. Eclipses were detected using data obtained with the Transiting Exoplanet Survey Satellite (TESS). The presence of eclipses places Thuban into the class of binaries known as eclipsing binaries. Properties Thuban has a spectral class of A0III, indicating its similarity to Vega in temperature and spectrum, but more luminous and more massive. It has been used as an MK spectral standard for the A0III type. Thuban is not a main-sequence star; it has now ceased hydrogen fusion in its core. That makes it a white giant star, being 120 times more luminous than the Sun. It is 300 light-years away and its brightness is only decreased by 0.003 of a magnitude by intervening gas and dust. Conspiracy theory According to British conspiracy theorist David Icke, Alpha Draconis is the origin of blood-drinking, shape-shifting reptilians who lurk in underground bases and plot against humanity (with the aid of powerful figures including royalty). References External links Jim Kaler's Stars, University of Illinois: THUBAN (Alpha Draconis) NASA's: History of Precession :