Tauri zeta
Zeta Tauri (ζ Tau/ζ Tauri) is a binary star of the Constellation of the Taureau. Known old Babylonian like Shurnarkabti-sha-shutu, meaning " the star of the Bull towards the south, " Zeta Tauri appears among the most important stars of the well-known layout of the constellation, representing one of the horns of the celestial bull.
Of third magnitude (3,00), Zeta Tauri is a luminous Géante blue-white and heat of standard B located at approximately 417 light-years of the Ground. It is classified like variable star of standard Gamma Cassiopeiae. Its luminosity varies between magnitudes +2,88 and +3,17 because of a share of its intrinsic variability, and in addition because it is a Binaire with eclipses. The two components of the binary system are distant of approximately a UA and traverse their orbit in 133 days. His/her partner of Masse much lower is a yellow star of type G and magnitude +5,2. Star of 9 solar masses old of approximately 25 million years, Zeta Tauri is evolving/moving, being about to finish the fusion Hydrogène of its heart, if it is not already done.
She is approximately 5700 more luminous than our Sun and has a temperature of surface of 22000 Kelvin S. Ensemble, the Température and the Luminosité gives a Rayon equal to 5,2 times that of the Sun. However, which makes star really special, it is not its temperature or its raised luminosity, but its fast Rotation and its loss of mass. The number of equatorial revolutions was measured with 330 km/s, that is to say 115 times that of the Sun, the star carrying out a revolution on itself in only one day (to be compared with the period of 25 days solar rotation). The number of revolutions, which are still far from being equal to that necessary to break star, is connected to the thick matter disc which surrounds it. The disc emits brilliant emission lines of the Hydrogène in the fields red and blue of the spectrum, making Zeta Tauri one of the " stars Be " most known. The star and the disc are both enough large to make it possible to measure their angular Diamètre S. The diameter of the disc is equal to 64 solar diameters.
Zeta Tauri indirectly played a big role in the study of the Supernova E. Indeed, the historical Supernova SN 1054 had been described (at the time under the name of “invited star”) by the Astronome S of Far East, which had given a localization compared to a star of it that they named Tianguan and which later was identified as being Zeta Tauri. It is armed with this information which it could be established at the beginning of the 20th century (it initially by Edwin Hubble seems) that the remainder of this explosion corresponded in fact to the Nébuleuse of the Crab, whose precise age thus knew to be measured.
Reference
- Kaler, Jim (2005) " STARS: Tauri" zeta;. Consulted on October 9th, 2007.
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