Proxima Centauri is the nearest star to the Sun, a small red dwarf too faint to see with the naked eye, bound loosely to the bright pair of Alpha Centauri.
At a glance
| type | red dwarf (class M) |
|---|---|
| distance from the Sun | 4.24 light-years (1.3 pc) |
| its light left it | 4.24 years ago |
| luminosity | 0.0017 × the Sun |
| radius | 0.15 × the Sun |
| surface temperature | 3,040 K |
Read off the piece’s own catalogue, the same values it draws with.
About Proxima Centauri
Proxima is a red dwarf: a star with a fraction of the Sun’s mass, burning its hydrogen so slowly that it will outlive the Sun by an enormous margin. Its surface is cool enough to glow a deep orange-red, and it gives off so little light that, despite being the closest star of all, it cannot be seen without a telescope. Its name is simply Latin for “nearest”.
It is a flare star. Its interior churns all the way through, which knots its magnetic field, and every so often that field snaps and the star brightens sharply within minutes. Those outbursts matter because Proxima has planets. Proxima b, found from the tiny back-and-forth wobble it imposes on the star’s light, orbits in the zone where the starlight would be gentle enough for liquid water, and a smaller world, Proxima d, orbits closer in.
Proxima travels through space with Alpha Centauri A and B, on an orbit so wide that a single circuit takes far longer than recorded history. Together the three make up the nearest star system to our own, in the southern constellation of Centaurus.
What you see in the piece
Fly to it and the disc fills with dark spots and the occasional flare, painted from its measured temperature as a dim red ember, with its catalogued planets on their orbits. From Earth, in HUMAN EYE, it is not there at all: it lies far below the limit of the eye.
Measured or modelled
Whether Proxima b could hold an atmosphere under the star’s flares is unknown; a third planet, Proxima c, has been proposed but not confirmed.
Questions
How far away is Proxima Centauri?
Proxima Centauri is 4.24 light-years (1.3 pc) from the Sun, so the light reaching us now left it 4.24 years ago.
Can you see Proxima Centauri with the naked eye?
No. Its luminosity is only 0.0017 × the Sun, so even this close it needs a telescope.