Aldebaran
Aldebaran is an orange giant star in Taurus and the constellation’s brightest star. It lies in the foreground of the Hyades cluster, not within it.
Orange giant: A luminous, evolved star whose surface temperature gives it an orange appearance. Aldebaran is a nearby example of this stellar class.
Taurus (constellation): A constellation of the zodiac in the northern celestial hemisphere. Aldebaran is Taurus’s brightest star and marks the Bull’s eye.
Arabic star names: Traditional star names derived from Arabic, many preserved in modern astronomical usage. Aldebaran’s name comes from an Arabic expression associated with following the Pleiades.
Celestial navigation: The determination of position using measured directions to celestial bodies. Aldebaran’s brightness and recognizable position have made it a practical sky landmark.
Aldebaran b: A proposed planetary companion to Aldebaran whose existence has not been securely established. It is a debated interpretation of the star’s velocity variations, not a confirmed planet.
Stellar classification: The system astronomers use to describe stars by properties such as spectrum, temperature, and luminosity. Aldebaran’s spectrum places it among cool, evolved stars.
Hyades: An open star cluster in Taurus, among the nearest clusters to the Solar System. Aldebaran appears in front of the Hyades but is not a cluster member.
IAU Working Group on Star Names: The International Astronomical Union body responsible for standardizing traditional star names. The group formally recognizes Aldebaran as the star’s standard name.
Occultation: An event in which one celestial body passes in front of another from an observer’s viewpoint. The Moon periodically occults Aldebaran, enabling precise measurements of its position and angular size.
Hyades moving group: A stream of stars sharing motion through space, associated with the Hyades cluster. Aldebaran’s sky position suggests cluster association, but its distance and motion exclude membership.