Red Giant Star Aldebaran: The Follower of the Pleiades in Taurus

~6 min

Aldebaran, one of the sky’s brightest stars, shines near the famous Pleiades in the zodiac constellation Taurus. It’s a stellar wonder you don’t want to miss! Locate the star easily with our free Sky Tonight app. And now, let's dive into this article to explore its rich mythology, physical characteristics, and upcoming events.


Aldebaran – key star facts

  • Official names: Aldebaran, Alpha Tauri, Alpha Tau, α Tau
  • Catalog designations: HR 1457, HIP 21421, HD 29139
  • Constellation: Taurus
  • Star type: class K5 III red giant
  • Right ascension: 04 h 35 m 55.23 s
  • Declination: +16° 30′ 33.49″
  • Apparent magnitude: 0.85
  • Mass: 1.16 solar masses
  • Luminosity: 439 L
  • Radius: 44 solar radii
  • Surface temperature: 3,900 K
  • Distance from the Earth: 66.5 light-years
  • Rotation period: 520 days

What type of star is Aldebaran?

Aldebaran is a red giant star. Such stars are entering the late stages of its life cycle, having exhausted the hydrogen fuel in its core and now fusing helium.

Curious to learn more about the life cycle of stars? Check out our colorful and easy-to-understand infographic on the topic.

Life Cycle of a Star
Explore the evolution of stars: from the vastness of stellar nurseries to the death throes of supernovae and the enigmatic allure of black holes.
See Infographic

What is the temperature and color of Aldebaran?

Red giant stars, such as Aldebaran, have relatively low surface temperatures. Aldebaran has a surface temperature of about 3,910 K, which is about 1,5 times cooler than our Sun’s.

For us on the Earth, the temperature of stars is manifested in their color. Aldebaran shines with an orange-red hue, which is a common trait for red giants.

How old is Aldebaran?

At around 6.4 billion years old, Aldebaran is significantly older than our Sun. In another few hundred million years, the star’s nuclear reactions will stop and Aldebaran will turn into a colorful planetary nebula – a radiating cloud of gas and dust.

How big is Aldebaran?

Aldebaran is 44 times larger than the Sun. If Aldebaran were to replace the Sun at the center of the Solar System, the star's surface would extend halfway to the orbit of Mercury and would cover 20 degrees of our sky (this is more than the width of the Big Dipper, including the handle).

Where is Aldebaran in the sky?

Aldebaran is the brightest star in the constellation Taurus. It appears to be part of the Hyades cluster, as seen from the Earth, but it is actually about 60 light-years closer to us than the cluster. It’s the 14th brightest star in the sky and is quite easy to find if you know where to look.

How to find Aldebaran – the easiest way

The easiest way to locate Aldebaran, especially if you are searching for the first time, is to use an astronomy app, like Sky Tonight. Here is a step-by-step guide:

  • Type the star’s name in the app’s search.
  • Tap the blue target button to the right of the matching result. The app will show you the star's position on the sky map.
  • Tap the blue compass button at the bottom right of the screen, or just point your device at the sky. The app will use your device’s location to align the screen image with the real sky above you.
  • Move your device following the white arrow until you see bright orange Aldebaran on the screen and in the real sky.
Find Aldebaran with Sky Tonight
Try the free Sky Tonight app to quickly locate Aldebaran. It uses your device’s location to match the on-screen view with the real night sky above you.

How to find Aldebaran using Orion’s Belt

If you don't have a stargazing app at hand, you can use the constellation Orion to guide your way to Aldebaran. Find the Orion's Belt asterism, the prominent line of three stars close together, and extend that line to the west (to the right if you're in the Northern Hemisphere). This line will lead you directly to Aldebaran, the first bright star along the way. We've created a poem for you, beautifully illustrated with a 3D video, showing the positions of Orion and Taurus relative to each other. Take a look – it's stunning and will help you remember!

In areas with minimal light pollution, you may also see the V-shaped Hyades cluster surrounding Aldebaran, further confirming its identity.

How to find Aldebaran
Use the famous Orion's Belt asterism to help you navigate to Aldebaran.

When to see Aldebaran?

Aldebaran is best seen from December to early May. This is when the star is well-placed in the evening and night sky. From May 14 to June 21, Aldebaran, as well as its entire parent constellation Taurus, is not observable because Taurus hosts the Sun. By the end of June, Aldebaran reappears in the predawn sky.

Aldebaran is located near the ecliptic, the path in the sky where Solar System objects appear to travel. That's why the star often encounters the Moon and planets.

August 4: Mars near Aldebaran

On August 4, at 01:20 GMT, Mars will pass within 4°24' of Aldebaran. The objects will rise late at night and be easily visible to the naked eye. Check out our infographic on distinguishing stars from planets to avoid confusing the reddish Mars with the red-orange Aldebaran. The scene will also feature bright Jupiter, the beautiful Pleiades and Hyades clusters, and the slightly dimmer Uranus, making it a fantastic photo opportunity!

Stars VS Planets
How much does a star differ from a planet? What's an easy way to tell them apart in the sky? Read this infographic to learn the answers.
See Infographic
Mars and Aldebaran
Mars will pass close to Aldebaran on August 4. The reddish planet and the red-orange star will shine beautifully together.

July 13, 2025: Venus near Aldebaran

The next meeting of Aldebaran with a planet will occur on July 13, 2025. At 08:32 GMT, Venus will be located just 3°06′ from Aldebaran. Both objects will be easily visible to the naked eye a couple of hours before local sunrise. At this time, Venus will be positioned within the so-called Golden Gate of the Ecliptic, an asterism formed by the Pleiades and Hyades star clusters in the constellation Taurus. This will be a fantastic opportunity for astrophotography, so don’t miss it!

Aldebaran near Venus, 2025
Venus will pass close to Aldebaran on July 13, 2025. The beautiful Pleiades and Hyades star clusters will also shine nearby, adding up to the celestial scene.

June 16, 2027: Venus near Aldebaran

On June 16, 2027, Venus will pass near Aldebaran. At 10:11 GMT, it will be located just 4°42′ from the reddish star. Both objects will be easily visible to the naked eye a couple of hours before local sunrise. Dimmer Uranus will also be located nearby, but it will only be visible with a pair of binoculars and may be completely outshined by the rising Sun.

Aldebaran near Venus, 2027
Venus will pass close to Aldebaran on June 16, 2027. The pair will be visible in the sky for a couple of hours before sunrise.

Aldebaran name & mythology

The name "Aldebaran" comes from the Arabic "al Dabarān," which means "the follower." This is because Aldebaran seems to follow the Pleiades star cluster, which is also located in the constellation Taurus.

Aldebaran has been observed and honored for thousands of years. In Babylonia, around 3000 BC, it was known as "The Leading Star of Stars" because the arrival of the constellation Taurus marked the vernal equinox, the beginning of the Babylonian year. In Persia, Aldebaran was one of the four Royal Stars that symbolized the four seasons, along with Regulus, Antares, and Fomalhaut. The Mesopotamians called Aldebaran the "Messenger of Light."

In modern times, the star is often depicted as the bull's orange eye. Interestingly, however, in the Middle Ages it was called Cor Tauri – the heart of the bull. Different cultures had their own interpretations: some Native American tribes saw Taurus as the head of a bison, the Inuit people of the Arctic saw Aldebaran as a polar bear.

Interesting facts about Aldebaran

A star system

Aldebaran might not be alone! It could be part of a multiple star system with a tiny, faint companion called Alpha Tauri B. This red dwarf star has a very low magnitude of 13.6. However, it's so faint that astronomers aren’t sure if Alpha Tauri B is actually close to Aldebaran or just appears that way from Earth.

There are also three more stars near Aldebaran in the sky – Alpha Tauri C, D and F. In fact, two of them (Alpha Tauri C and D) are a binary system, but they aren’t related to Aldebaran. They are much farther away and belong to the Hyades cluster.

A potential exoplanet host

Aldebaran may have at least one exoplanet called Aldebaran b, which is about 6.5 times the size of Jupiter. Discovered in 1993 and confirmed in 2015, its existence was later questioned again. In a paper published in 2019, scientists suggested that there should be either two or no exoplanets around Aldebaran. For now, Aldebaran b remains a candidate exoplanet until more data provides clarity.

If Aldebaran b does exist, it is an unlikely place for carbon-based life. Its surface temperature should be around 1,500 K and receive significant radiation from Aldebaran.

A destination for the Pioneer 10 probe

The Pioneer 10 probe, launched in 1972, is on its way to Aldebaran. Although it no longer communicates with the Earth, it will reach Aldebaran in about 2 million years. At Carl Sagan's suggestion, Pioneer 10 and its twin Pioneer 11 carry gold-anodized aluminum plaques depicting human figures and symbols to convey information about the spacecraft's origins to potential extraterrestrial finders.

Pioneer 10 probe
A design etched into a gold-anodized aluminum panel mounted on the Pioneer 10 spacecraft. Designed by Carl Sagan and Frank Drake, with artwork by Linda Salzman Sagan.

Aldebaran star: conclusion

Aldebaran is the brightest star in Taurus. It holds a special place in the constellation, often depicted as the fiery orange eye of the celestial bull. As the 14th brightest star in the entire night sky, Aldebaran is easy to find. It's also particularly interesting because it often meets Solar System objects such as planets or the Moon in the sky. Use our Sky Tonight app to guide your stargazing adventures and enjoy the beauty of Aldebaran!