Aldebaran: Brightest Star in Taurus

stars Jan 14, 2024

Aldebaran is an orange giant star and the brightest star in the constellation Taurus. It is approximately 65 light-years away from Earth. Its luminosity, or brightness, is over 500 times that of our sun.  Numerous ancient cultures have observed and made reference to the star, which is plainly visible with the naked eye. Aldebaran is part of the Hyades star cluster, although it is not physically associated with the cluster, as it is much closer to Earth. Aldebaran holds cultural significance in different mythologies and has been a subject of interest for astronomers and skygazers throughout history.


It is one of the easiest stars to see in the night sky, because of its brightness and proximity to one of the sky's most visible celestial objects, such as the Pleiades and Hyades star clusters. Orion’s belt is also used when trying to find this star. The name Aldebaran is derived from the Arabic phrase meaning "the follower," as it appears to follow the Pleiades star cluster across the sky. It first appears in late November and can be seen through February into March. 

To understand why Aldebaran and our sun are so different, we have to look at the life cycle of a star. This is because the stars are at different stages of their lives.  Our sun is still in the main sequence phase, where the forces of gravity and fusion are balanced. It's a steady star. On the other hand, Aldebaran has evolved off the main sequence band. This means a star no longer fuses hydrogen at the core. Instead, hydrogen fusion occurs in the outer layers, causing the star to expand.  Helium fusion now takes place in the core, and the surface temp cools down.  They glow brighter because of their enormous size. 

 Our Sun is a main sequence star, while Aldebaran is a red giant star. It is cooler and larger than the Sun, which is why it is so bright. 


In 2015, an exoplanet was detected called Aldebaran b, a Jupiter-like gas giant planet.  This planet has a close orbit to the Aldebaran, and does not sit in the range in which liquid water can exist.  It’s mass is 6.47 Jupiters, it takes 1.7 years to make one orbit around Aldebaran, and it was detected through its radial velocity. 

Pioneer 10, a NASA space probe launched in 1972, will come into contact with the Aldebaran system in 2 million years, as it is headed in that direction of the sky. Pioneer 10 was the first artificial satellite to achieve the escape velocity needed to leave the solar system.  A trace of our civilization will be near this star system.


Additional Resources to Explore:

▶ Stellarium online planetarium: 

▶ 100,000 Stars: