Adara
HIP 33579; Epsilon CMa; 21 CMa
Physical Properties
Position & Identifiers
Visibility
Set a location in User Settings to see visibility data.
Multiple Star System
Eyepiece View
Sep: 7.9″ · PA: 162° · N up, E left
Resolved · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 3.1″
Size Comparison
Stellar Lifecycle
Spectral Classification
Hertzsprung-Russell Diagram
Blackbody Spectrum
Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
Stellar Notes
Survey Image
Loading survey image…
About Adara
Description
Adara (Epsilon Canis Majoris) is the second brightest star in Canis Major at magnitude 1.50, located about 430 light-years from Earth. It is a blue giant of spectral type B2Iab, about 11 times the mass of the Sun and roughly 38,000 times more luminous. Adara is one of the strongest sources of extreme ultraviolet radiation in the sky as seen from Earth.
Observing Tips
Adara sits at the hindquarters of Canis Major, forming part of the distinctive triangle of stars south of Sirius. Its blue-white color is evident through binoculars. Adara has a faint companion (magnitude 7.5) at about 7.5 arcseconds separation, resolvable in a small telescope. The star is visible from both hemispheres. Best observed from January through March.
History
The name Adara comes from the Arabic 'al-Adhara' meaning 'the maidens' or 'the virgins.' About 4.7 million years ago, Adara was the brightest star in Earth's sky, shining at magnitude -3.99 when it was only about 34 light-years away. Since then, its proper motion has carried it much farther from the Sun.
Fun Facts
Adara was once the brightest star in Earth's sky — it holds the record for the brightest apparent magnitude ever achieved by any star other than the Sun as seen from Earth's position, reaching nearly magnitude -4 about 4.7 million years ago. It is the strongest source of photons in the extreme ultraviolet range (504-912 Å) in the sky.