this is a main-sequence star, a neutron star, or a white dwarf. If it is a main sequence star, then the mass indicates it may have a stellar classification of G4. The spectrum of the primary component has a stellar classification of B2 IIIpe. A luminosity class of 'III' indicates this is a giant star that has exhausted the hydrogen at its core and evolved away from the main sequence. The 'p' suffix indicates an unspecified chemical peculiarity in the spectrum, while 'e' is used for stars that display emission lines. For Be stars such as this, the emission lines are produced by a rotating circumstellar disk of gas, made of material that has been ejected from the star's outer envelope. An oscillatory pattern in this spectrum is being caused by a single-armed spiral density wave in the disk. The disk may be precessing from the gravitational influence of the secondary component. Zeta Tauri shows variation in its spectrum and brightness. The General Catalogue of Variable Stars lists it as an eclipsing variable and a Gamma Cassiopeiae variable, but it may not be either. Hrvoje Božić and Krešimer Pavlovski, of Hvar Observatory in Croatia, monitored the brightness of Zeta Tauri from 1981 to 1986 and noticed an eclipse like effect in the light curve. A latter study of all the available photometric data, including from the Hipparcos spacecraft, failed to confirm the presence of eclipses. See also Chinese constellations White Tiger (mythology) References Tauri, Zeta B-type giants Gamma Cassiopeiae variable stars Spectroscopic binaries Taurus (constellation) Tianguan Tauri, 123 1910 026451 037202 BD+21 0908