Alpha Centauri A is the nearest star like the Sun, a yellow star that, with its partner B, shines as the brightest point in the southern constellation Centaurus.
At a glance
| type | yellow star (class G) |
|---|---|
| distance from the Sun | 4.37 light-years (1.34 pc) |
| its light left it | 4.37 years ago |
| luminosity | 1.52 × the Sun |
| radius | 1.22 × the Sun |
| surface temperature | 5,790 K |
| constellation | Centaurus (Centaur) |
Read off the piece’s own catalogue, the same values it draws with.
About Alpha Centauri A
Alpha Centauri A is a yellow main-sequence star, a little larger and brighter than the Sun and of much the same type, and somewhat older. It orbits Alpha Centauri B, a slightly smaller and cooler orange star, and to the eye the two merge into a single point that ranks just behind Sirius and Canopus as one of the brightest stars in the night sky. Its traditional name is Rigil Kentaurus, the foot of the Centaur.
It was one of the first stars to have its distance measured. Thomas Henderson, observing from the Cape of Good Hope, tracked its tiny seasonal shift against the background as the Earth went round the Sun, the parallax, and showed it was very close. His was among the first distances to a star ever measured; only Bessel’s result for the pair that includes 61 Cygni A was published first.
With its companion B and the red dwarf Proxima, Alpha Centauri is the nearest star system to the Sun. It lies too far south to be seen from most of Europe and North America; from the southern hemisphere it and Hadar point the way to the Southern Cross.
What you see in the piece
Fly to it and the point splits into two stars, yellow A and the more orange B, circling each other. A candidate giant planet drawn in its system is marked as a candidate, because that is all it is so far.
Measured or modelled
A giant planet imaged in infrared around A by the James Webb Space Telescope is still a candidate awaiting confirmation.
Questions
What is the closest Sun-like star?
Alpha Centauri A, a yellow star (class G) 4.37 light-years (1.34 pc) away, with a luminosity of 1.52 × the Sun.
Is Alpha Centauri the brightest star?
No. Seen together, A and B make the third brightest star in the night sky, after Sirius and Canopus.