Aldebaran size and scale context

Aldebaran is a red giant branch star in Taurus with a cool orange surface and a diameter about 45 times the Sun’s. It lies in front of the Hyades cluster by chance, so it appears to sit among the bull’s-head stars without actually belonging to that group. Read its scale context, comparisons, and journey links on the canonical object page.

PolluxK-type orange giant star·12.5 million km

Sagittarius A*Supermassive black hole·24.5 million km

ArcturusK-type orange giant star·35 million km

AldebaranK-type red giant star·62.8 million km

RigelBlue supergiant star·103 million km

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Stars

Arcturus

Arcturus is a bright orange giant and the brightest star in the northern celestial hemisphere. It also races unusually fast across the sky for such a bright star, shifting by about two arcseconds per year because of its high motion relative to the Sun.

Scale fact35 million kmdiameter

Object class: K-type orange giant star
Mass: ~1.1 solar masses
Temperature: ~4,300 K surface
Estimated age: ~7.1 billion years
Composition: Hydrogen and helium

Stars

Aldebaran

Scale fact62.8 million kmdiameter

Object class: K-type red giant star
Mass: ~1.03 solar masses
Host: Aldebaran system
Estimated age: ~6.4 billion years
Composition: Hydrogen and helium
Temperature: ~3,900 K surface

Stars

Rigel

Rigel is the blue-white supergiant that marks Orion’s foot and dominates the constellation’s lower half. Although it looks solitary to the eye, it is actually part of a multiple-star system built around a spectacularly luminous hot primary star.

Scale fact103 million kmdiameter

Object class: Blue supergiant star
Mass: ~21 solar masses
Temperature: ~12,000 K surface
Estimated age: ~8 million years
Composition: Hydrogen and helium