Pleione

Pleione is a binary star and the seventh-brightest star in the Pleiades star cluster (Messier 45). It has the variable star designation BU Tauri (BU Tau) and the Flamsteed designation 28 Tauri (28 Tau). The star is located approximately from the Sun, appearing in the constellation of Taurus. Pleione is located close on the sky to the brighter star Atlas, so is difficult for stargazers to distinguish with the naked eye despite being a fifth magnitude star. The brighter star of the Pleione binary pair, component A, is a hot type B star 184 times more luminous than the Sun. It is classified as Be star with certain distinguishing traits: periodic phase changes and a complex circumstellar environment composed of two gaseous disks at different angles to each other. The primary star rotates rapidly, close to its breakup velocity, even faster than Achernar. Although some research on the companion star has been performed, stellar characteristics of the orbiting B component are not well known. Nomenclature 28 Tauri is the star's Flamsteed designation and BU Tauri its variable star designation. The name Pleione originates with Greek mythology; she is the mother of seven daughters known as the Pleiades. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included Pleione for this star. It is now so entered in the IAU Catalog of Star Names. Visibility