Gamma Centauri — Double Star in Centaurus
About Gamma Cen
Description
Gamma Centauri is a binary star system of spectral type A1IV at magnitude 2.17 in Centaurus. It consists of two nearly identical A-type stars orbiting each other every 83 years. Located about 130 light-years from Earth, the combined luminosity is roughly 120 times solar.
Observing Tips
Gamma Cen lies in the body of Centaurus, between the brilliant Alpha/Beta pointer pair and the constellation's northern stars. It can be resolved as a double star in a moderate telescope, with the two components currently about 1 arcsecond apart. Only visible from the southern hemisphere. Best observed March through July.
History
Gamma Centauri has no widely used traditional name. The double star nature was discovered by James Dunlop in 1826. Centaurus is one of the oldest and largest constellations, representing the wise centaur Chiron of Greek mythology.
Fun Facts
Gamma Cen's two nearly identical stars make it a 'twin' double star system — both components are A1 subgiants of similar brightness, making the pair appear as two equally matched jewels when resolved in a telescope.
Observe
1Physical Properties
2Position & Identifiers
3How easy to split?
| Telescope | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| 80 mm refractor 80mm refr. | V. hard | V. hard | V. hard |
| 150 mm Newton 150mm Newt. | Hard | Hard | Hard |
| Celestron C8 (203 mm SCT) C8 203mm | Hard | Hard | Hard |
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
4Visibility
Set a location in User Settings to see visibility data.
5Multiple Star System Triple
Separation over time
Apparent separation over time, computed from ORB6 orbital elements. Steep curves indicate fast-changing pairs — catch them while they're splittable.
Eyepiece View
A: 2.2 · B: 2.9 · Sep: 0.8″ · PA: 19° · N up, E right
Unresolved · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 2.3″
Explore
7
Size Comparison
8
Compare Stars
9
Spectral Classification
10
Hertzsprung-Russell Diagram
11
Stellar Lifecycle
12
Blackbody Spectrum
13
Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
14
Stellar Fusion
Discover
15Stellar Notes
16
Light Travel Time Machine
17
Relativistic Travel
Nearby in the Sky
Other targets within a few degrees — pan your scope a little and keep exploring.
Visibility scores assume a 150 mm Newton at Bortle 4.
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