Proxima Centauri
Star · Red dwarf
Proxima Centauri is the closest star to the Sun. It is a small, cool red dwarf – too faint to see without a telescope. It belongs to the Alpha Centauri triple-star system.
- 4.2 light-years awayEven light – the fastest thing there is – needs 4.2 years to get here.
- ~1/7 of SunSize
- At least 2Planets
Take a closer look
A stormy little star
Proxima Centauri is a flare star. Every so often a sudden blast of energy erupts from its surface, making it shine many times brighter for a few minutes. These flares send out strong ultraviolet light and X-rays – bad news for any planet hoping to keep a gentle atmosphere.
A year of 11 days
The planet Proxima b is a little heavier than Earth and circles its star in just 11 days. Seen from there, Proxima would look about three times wider than the Sun does from Earth, but glow a dim reddish colour. One side of the planet may always face the star.
A trillion-year candle
Small red dwarfs like Proxima use their fuel extremely slowly. Our Sun will shine for about 10 billion years in total, but Proxima will keep glowing for trillions of years – far longer than the Universe has existed so far. No red dwarf has ever had time to die.
How we found out
- 1915
Robert Innes, working in Johannesburg, South Africa, discovers Proxima.
- 2016
Astronomers find Proxima b, a planet in the zone where liquid water might be possible.
- 2022
A third possible planet, Proxima d, is reported – one of the lightest planets ever detected.
How could humans ever visit another star?
Ideas include tiny probes pushed by giant lasers to a fifth of the speed of light (the Breakthrough Starshot idea). Maybe you will invent a better way!
See it yourself
Too faint for your eyes, and best from the Southern Hemisphere. Its bright neighbour Alpha Centauri is easy to see.
From the encyclopedia
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