Home – Brightest Stars – AldebaranAldebaranby adminSeptember 5, 2014March 27, 2026Aldebaran, Alpha Tauri, also known as the Eye of Taurus, is an orange giant star located at a distance of 65 light years from Earth. It is the brightest star in Taurus constellation and the 14th brightest star in the night sky. Aldebaran has a luminosity 518 times that of the Sun (153 times in visible light). The name Aldebaran (pronounced /ælˈdɛbərən/) comes from the Arabic word al-dabarān, meaning “the follower.” The name refers to the Pleiades cluster (Messier 45), which the star appears to be following across the sky. Orange or reddish in colour, Aldebaran has the stellar classification K5 III and an apparent magnitude that varies from 0.75 to 0.95. It is classified as a slow irregular type LB variable star and has the designation CSV 6116 in the Catalogue of Suspected Variable stars. The star’s variability is not visible to the unaided eye. Aldebaran has evolved off the main sequence stage of its life cycle and exhausted the supply of hydrogen fuel in its core. It is now fusing hydrogen in a shell around the helium core. As a result, the star has brightened and expanded to a radius 44.2 times that of the Sun. <img fetchpriority="high" decoding="async" aria-describedby="caption-attachment-6758" class="wp-image-6758 size-full" src="https://www.constellation-guide.com/wp-content/uploads/2014/09/Aldebaran-size.png" alt="aldebaran sun comparison" width="483" height="480" srcset="https://www.constellation-guide.com/wp-content/uploads/2014/09/Aldebaran-size.png 483w, https://www.constellation-guide.com/wp-content/uploads/2014/09/Aldebaran-size-150x150.png 150w, https://www.constellation-guide.com/wp-content/uploads/2014/09/Aldebaran-size-300x298.png 300w" sizes="(max-width: 483px) 100vw, 483px" /> Aldebaran and Sun in scale. If Aldebaran were to replace the Sun in the centre of the solar system, the star’s surface would extend halfway to the orbit of Mercury and would extend across 20 degrees in our sky. The helium burning stage typically lasts tends to hundreds of millions of years, or about 700 million years for a star with a mass equal to the Sun’s, and Aldebaran has 1.7 solar masses. Aldebaran will reach about 800 solar luminosities within the next few million years. Eventually, it will lose much of its current mass through its strong stellar wind and expel its outer envelope to form a planetary nebula, leaving behind a white dwarf. The star is cooler than the Sun, with a surface temperature just under 4,000 K, compared to the Sun’s 5,800 K. It is a very slow rotator, completing a rotation every 643 days. <img decoding="async" aria-describedby="caption-attachment-6764" class="wp-image-6764" src="https://www.constellation-guide.com/wp-content/uploads/2014/09/Aldebaran-location-300x273.png" alt="find aldebaran,where is aldebaran in the sky" width="500" height="455" srcset="https://www.constellation-guide.com/wp-content/uploads/2014/09/Aldebaran-location-300x273.png 300w, https://www.constellation-guide.com/wp-content/uploads/2014/09/Aldebaran-location-640x582.png 640w, https://www.constellation-guide.com/wp-content/uploads/2014/09/Aldebaran-location.png 689w" sizes="(max-width: 500px) 100vw, 500px" /> Aldebaran location Aldebaran is very easy to find in the sky. To locate the star, observers can just follow the line formed by the three stars of Orion’s Belt to the right (in northern latitudes) or to the left (in the southern hemisphere). Aldebaran is the first bright star that appears along that line. The best time of year to observe Aldebaran is in the fall and winter months, when the star and Orion’s Belt rise in the east in the evening and move to the northwest over the course of the night. Table of Contents Toggle Star systemFacts Star system There are five faint stars appearing near Aldebaran, but most of them are just optical companions. The stars were given designations Aldebaran B through Aldebaran F in the order of discovery, while the primary star is designated Aldebaran A. <img decoding="async" aria-describedby="caption-attachment-6757" class="wp-image-6757 size-large" src="https://www.constellation-guide.com/wp-content/uploads/2014/09/Aldebaran-640x425.jpg" alt="alpha tauri,hyades,aldebaran star" width="640" height="425" srcset="https://www.constellation-guide.com/wp-content/uploads/2014/09/Aldebaran-640x425.jpg 640w, https://www.constellation-guide.com/wp-content/uploads/2014/09/Aldebaran-300x199.jpg 300w, https://www.constellation-guide.com/wp-content/uploads/2014/09/Aldebaran.jpg 1000w" sizes="(max-width: 640px) 100vw, 640px" /> Aldebaran and the Hyades cluster. Image: Thomas Bresson Aldebaran B is a red dwarf with the stellar classification M2V. It has an apparent magnitude of 13.6 and an absolute magnitude of 11.98. It is separated by about 607 astronomical units from Aldebaran A. Several surveys have indicated that the two stars may share a common proper motion and may not be just optical companions, but form...