Proxima Centauri is the closest star to the Sun, just 4.24 light-years away. It is a small, cool red dwarf, the third member of the Alpha Centauri system, and far too faint to see with the naked eye (magnitude 11). It has at least two planets, including Proxima b, an Earth-mass world in its habitable zone.
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Proxima Centauri at a glance
| Other names | Alpha Centauri C, Proxima |
|---|---|
| Constellation | Centaurus |
| Brightness | Magnitude +11.1, needs a telescope |
| Distance | 4.24 light-years, the closest star to the Sun |
| Type | Red dwarf (M5.5), flare star |
| Mass | About 12% of the Sun |
| Size | About 15% of the Sun’s diameter |
| Temperature | About 3,000 K |
| Known planets | Proxima b (2016) and Proxima d (2022); Proxima c unconfirmed |
| Best time to see it | Evenings around June (highest at about 9 p.m.) |
| Where on Earth | Visible from everywhere south of about 27°N; never sets south of about 27°S |
The nearest star, but you can’t see it
It surprises many people that the closest star to the Sun is invisible to the naked eye. Proxima Centauri is a red dwarf, the most common kind of star in the Milky Way. It has only about 12% of the Sun’s mass, is about 15% of its diameter (a little bigger than Jupiter), and gives out less than 1% of the Sun’s light, most of it as infrared. At magnitude 11 it needs a telescope of at least 7 to 10 cm aperture and a good star chart, and you must be in the Southern Hemisphere or the tropics to see it.
Proxima was discovered in 1915 by the Scottish astronomer Robert Innes in South Africa, who noticed a faint star sharing the motion of Alpha Centauri across the sky. It lies about 0.2 light-years from the bright pair Alpha Centauri A and B and orbits them very slowly, taking roughly half a million years per orbit.
Proxima Centauri’s planets
In 2016 astronomers using the European Southern Observatory’s telescopes announced Proxima b, a planet with at least about 1.1 times Earth’s mass that orbits the star every 11.2 days. Because Proxima is so dim, that tight orbit places the planet in the star’s habitable zone, where liquid water could in principle exist on the surface. In 2022 a second, smaller planet, Proxima d, about a quarter of Earth’s mass with a 5-day orbit, was announced, and in 2025 the new NIRPS infrared spectrograph independently re-detected Proxima’s planets. A third, more distant candidate, Proxima c, remains unconfirmed.
Whether Proxima b could support life is an open question. It is probably tidally locked, with one side always facing the star, and it is exposed to intense radiation.
A violent flare star
Proxima is a flare star: magnetic activity on its surface produces sudden flares that can make the star brighten dramatically for minutes. In 2019 astronomers recorded a flare that made Proxima about 14,000 times brighter in ultraviolet light for a few seconds. Flares like this, together with strong stellar winds, could strip away the atmospheres of nearby planets, one of the main reasons scientists are cautious about the habitability of Proxima b.
How far is 4.24 light-years?
About 40 trillion kilometres, or roughly 268,000 times the distance from Earth to the Sun. Light takes 4.24 years to make the trip, so we see Proxima as it was more than four years ago. The fastest spacecraft ever launched would need thousands to tens of thousands of years. Proxima will stay the Sun’s nearest stellar neighbour for many thousands of years; in the far future, as stars move through the galaxy, others such as Ross 248 will take its place.
Where is Proxima Centauri in the sky?
Proxima lies in the constellation Centaurus, about 2 degrees from the brilliant Alpha Centauri, close to the Southern Cross. Its declination of about −63° means it never rises for observers north of about 27°N. From Australia, South Africa, South America and southern India it is up on autumn and winter evenings (April to July is best). The live tool above shows whether it rises where you are; remember it is only visible through a telescope.
A star that will outlive the Sun by trillions of years
Red dwarfs like Proxima burn their hydrogen fuel extremely slowly. While the Sun will run out of fuel in about 5 billion years, Proxima is expected to keep shining for trillions of years, far longer than the current age of the universe. It will slowly heat up and become a blue dwarf before finally fading as a white dwarf.
Frequently asked questions about Proxima Centauri
What is the closest star to Earth?
Apart from the Sun, the closest star is Proxima Centauri, 4.24 light-years away.
Can you see Proxima Centauri with the naked eye?
No. At magnitude 11 it needs a telescope, and it is only visible from the Southern Hemisphere and the tropics, south of about 27°N.
Does Proxima Centauri have planets?
Yes. Proxima b, an Earth-mass planet in the habitable zone, was found in 2016, and the smaller Proxima d in 2022. A third candidate, Proxima c, is unconfirmed.
Is Proxima Centauri part of Alpha Centauri?
Yes. It is the third star of the Alpha Centauri system, orbiting the bright pair A and B at a distance of about 13,000 times the Earth–Sun distance.
Could humans travel to Proxima Centauri?
Not with current technology. Today’s spacecraft would take tens of thousands of years. Proposed laser-driven light sails could one day make the trip in decades.
Sources: ESO: NIRPS first scientific results (2025); Proxima Centauri overview and references. Star data from standard catalogues; positions and rise/set times are calculated by SpaceTracker.live with the Astronomy Engine library.