Alpha Arae — Star in Ara
About Alpha Ara
Description
Alpha Arae is a blue main-sequence star of spectral type B2Vne at magnitude 2.95, the brightest star in Ara (the Altar). Located about 270 light-years from Earth, it is a Be star — rapidly rotating and surrounded by a gaseous disk. Its luminosity is about 5,800 times solar.
Observing Tips
Alpha Ara lies in the southern part of the small constellation Ara, south of the Scorpion's tail. It is a blue-white star in a rich part of the southern Milky Way. Only visible from the southern hemisphere and very low northern latitudes. Best observed June through August.
History
Alpha Arae has no traditional proper name. Ara is one of the 48 Ptolemaic constellations, representing the altar on which the gods swore their oath before battling the Titans.
Fun Facts
Alpha Ara's Be-star disk was one of the first to be spatially resolved using optical interferometry, confirming that Be stars do indeed have equatorial disks of ejected gas as theorized.
Observe
1Physical Properties
3How easy to spot?
| Equipment | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| Naked eye Naked eye | Easy | Easy | Easy |
| 50 mm finder 50mm finder | Easy | Easy | Easy |
| 150 mm telescope 150mm scope | Easy | Easy | Easy |
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
4Visibility
Set a location in User Settings to see visibility data.
5Survey Image
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Explore
7
Size Comparison
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Compare Stars
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Spectral Classification
10
Hertzsprung-Russell Diagram
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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
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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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