Betelgeuse size and scale context

Betelgeuse is a red supergiant nearing the end of its stellar life. Its dramatic dimming in 2019 and 2020 turned out to be caused by a dusty veil ejected from the star, giving astronomers a rare direct look at how giant stars shed material into space. Read its scale context, comparisons, and journey links on the canonical object page.

Spica AB-type giant/subgiant star·10.4 million km

PolluxOrange giant star·12.5 million km

ArcturusK-type giant star·35 million km

AldebaranRed giant branch star·62.8 million km

RigelBlue supergiant star·103 million km

DenebA-type supergiant star·280 million km

Eta Carinae ALuminous blue variable·334 million km

BetelgeuseRed supergiant star·1.05 billion km

Stephenson 2 DFK 49Extreme red supergiant star·1.6 billion km

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Between the smallest and the largest, perspective is everything.

About

Scale of Space is a scroll-based journey through the universe, placing objects on a single logarithmic scale so you can compare size across an unbroken range.

Guides turn parts of that scale into curated essays, while focused views let you explore the same range through specific groups of objects.

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Between the smallest and the largest, perspective is everything.

About

Scale of Space is a scroll-based journey through the universe, placing objects on a single logarithmic scale so you can compare size across an unbroken range.

Guides turn parts of that scale into curated essays, while focused views let you explore the same range through specific groups of objects.

Editorial

Solar System Planets From Electron to Atoms Stars To Scale Birth And Death Of Stars Black Holes To Scale

Views

Planets of the Solar System Stars of the Universe Black holes Subatomic scale

Open Scale of Space Browse all comparisons

Stars

Eta Carinae A

Eta Carinae A is the luminous blue variable primary in the Eta Carinae system, buried inside the Carina Nebula. Its dense wind makes the star’s surface hard to define, so this record uses an approximate visible stellar disk rather than a clean hydrostatic radius.

Scale fact334 million kmdiameter

Object class: Luminous blue variable
Mass: ~100 solar masses
Host: Eta Carinae system
Estimated age: ~3 million years
Composition: Hydrogen and helium
Temperature: ~15,000–25,000 K surface

Stars

Betelgeuse

Scale fact1.05 billion kmdiameter

Object class: Red supergiant star
Mass: ~15–20 solar masses
Temperature: ~3,600 K surface
Estimated age: ~8–14 million years
Composition: Hydrogen and helium

Stars

Stephenson 2 DFK 49

Stephenson 2 DFK 49 is an extreme red supergiant whose quoted size remains highly uncertain because its outer layers are diffuse and difficult to define. Even so, plausible estimates make it so enormous that its photosphere could approach or even engulf Jupiter’s orbit if placed at the center of the Solar System.

Scale fact1.6 billion kmdiameter

Object class: Extreme red supergiant star
Composition: Hydrogen and helium
Estimated age: ~10–20 million years
Temperature: ~4,000 K surface