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Information About

Epsilon Canis Majoris




name=Adhara }}
  Epoch J2000
  Constell Canis Major
  Ra 06h 58m 376s
  Dec -28&deg 58' 19"


  Class B2 II
  B-v -021
  U-b -093


  Radial V +27
  Prop Mo Ra 263
  Prop Mo Dec 229
  Parallax 757
  P Error 057
  Dist Ly 431
  Dist Pc 132





Epsilon Canis Majoris (ε CMa / ε Canis Majoris), is the second brightest star in the Constellation Canis Major , and One Of The Brightest Stars in the nighttime sky. It has the Bayer Designation "epsilon" despite being the second brightest and not the fifth brightest star in its constellation. It also has the traditional name '''Adhara''' (sometimes spelled '''Adara'''). The name is from the Arabic word '''عذارى''' ''‘aðāra’'', "virgins".

Adhara is a Binary Star , about 431 Light Year s distant from Earth. The main star possesses an Apparent Magnitude of +1.5 and belongs to the Spectral Classification B2. It has a surface temperature of 20,000°K and emits a total radiation equal to 20,000 times that of the Sun . If this star were at the same distance as Sirius , it would appear 15 times brighter than the planet Venus . This star is also one of the brightest known extreme ultraviolet sources in the sky.

The +7.5 magnitude companion star (the Absolute Magnitude amounts to −5.0) is at 7.5" away with a position angle of 161° of the main star. Despite the relatively large angular distance the components can only be resolved in large telescopes, since the main star is approximately 250 times brighter than its companion.


REFERENCES

  • E. Wilkinson, J.C. Green, R. McLean, and B. Welsh, "Extreme Ultraviolet Spectrum of epsilon Canis Majoris between 600-920 Å", Bull. American Astron. Soc., 188, #58.02.