Proxima Centauri

Updated

Details

Proxima Centauri is the nearest known star to the Sun, just over four light-years away. ESA describes it as a flare star prone to dramatic brightening, yet because it burns fuel so slowly it may remain on the main sequence for another four trillion years.

Proxima Centauri is the nearest known star to the Sun, but it is not a star that dominates the sky. It is a red dwarf: small, dim, and easy to miss unless you know exactly where to look. That makes Proxima feel less like a spotlight and more like a quiet but persistent ember.

At the same time, Proxima is not gentle in the everyday sense. It is a flare star, so its brightness can jump suddenly, and its surface is restless enough to keep astronomers alert. Yet the same slow-burning nature that makes it faint also makes it extraordinarily long-lived. Proxima can spend trillions of years on the main sequence, outlasting stars like the Sun by a vast margin.

That combination is what makes Proxima compelling. It shows that the closest star to us is not a miniature Sun but a different kind of engine altogether. Proxima turns the idea of a nearby star into something stranger: a small, active, durable source of light.

93,950km
Visual creditscaleofspace.org / CC BY-NC 4.0

Key facts

Category
Stars
Object class
M-type red dwarf star
Mass
~0.12 solar masses
Host
Alpha Centauri system
Scale fact
215,000 kmdiameter
Estimated age
~4.8 billion years
Composition
Hydrogen and helium
Temperature
~3,000 K surface

Scale context

Where Proxima Centauri sits on the full axis

By size on the journey, Proxima Centauri sits between Luhman 16 B and Lalande 21185. The band below compares Proxima Centauri with nearby M-type red dwarf star objects so the size jump stays easy to read.

Shared physical scale
415,235km
Proxima Centauri215,000 km
Lalande 21185543,000 km

Together, these objects make the size change around Proxima Centauri easy to compare at a glance.

Sources

References for Proxima Centauri

Measurements and descriptive context are compiled by the Scale of Space team from the references below. If you find an error, please let us know.

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