Betelgeuse facts for kids


Betelgeuse (from Arabic:إبط الجوزاء Ibṭ al-Jauzā’, meaning "the armpit of Orion") is a large red supergiant star in the Orion constellation. It is usually the ninth-brightest star in the night sky, and the second-brightest in Orion.
Betelgeuse is a semiregular variable star whose apparent magnitude varies between 0.2 and 1.2. This is the widest range of any first-magnitude star.
It is also one of the largest and most luminous observable stars. It has a radius between 950 to 1,000 times wider than the Sun. This means it is 1.322 to 1.392 billion kilometers in diameter. Betelgeuse was the first star other than the Sun whose size was known. The star's distance from Earth is about 640 light-years. Its average absolute magnitude is about −6.02.
Betelgeuse is less than 10 million years old. It evolves rapidly because of its high mass. It is moving through the interstellar medium at a speed of 30 km/s, creating a shock wave over 4 light-years wide.
Betelgeuse is now in a later stage of stellar evolution. It will rapidly go through its life cycle before exploding as a type II supernova sometime in the next million years.
An observation by the Herschel Space Observatory in January 2013 showed that the star's winds are crashing against the surrounding interstellar medium. Betelgeuse is one of the red supergiant stars to have a bow shock: others are Mu Cephei and IRC-10414. Betelgeuse can be seen at the upper left in Orion.
Alternate names
Betelgeuse is also called Alpha Orionis (α Orionis, abbreviated Alpha Ori, α Ori).
Related pages
- Orion (constellation)
- Rigel
- 119 Tauri, Antares, and Mu Cephei, other similar red supergiant stars
Images for kids
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Sir John Herschel in 1846
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1998/9 UV HST images of Betelgeuse showing asymmetrical pulsations with corresponding spectral line profiles
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AAVSO V-band magnitude of Betelgeuse, between September 2018 and August 2020
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AAVSO V-band light curve of Betelgeuse (Alpha Orionis) from Dec 1988 to Aug 2002.
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Infrared image of Betelgeuse, Meissa and Bellatrix with surrounding nebulae
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Image from ESO's Very Large Telescope showing the stellar disk and an extended atmosphere with a previously unknown plume of surrounding gas
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Exterior view of ESO's Very Large Telescope (VLT) in Paranal, Chile
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Hertzsprung–Russell diagram identifying supergiants like Betelgeuse that have moved off the main sequence
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An illustration of Orion (horizontally reversed) in al-Sufi's Book of Fixed Stars. Betelgeuze is annotated as Yad al-Jauzā ("Hand of Orion"), one of the proposed etymological origins of its modern name, and also as Mankib al Jauzā' ("Shoulder of Orion").
