Epsilon Canis Majoris


Epsilon Canis Majoris

Starbox begin
name=ε Canis Majoris
Starbox observe
epoch=J2000
constell=Canis Major
ra=06h 58m 37.6s
dec=−28° 58' 19"
appmag_v=1.51
Starbox character
class=B2 Iab
b-v=−0.13
u-b=−0.93
variable=
Starbox astrometry
radial_v=+27.3
prop_mo_ra=2.63
prop_mo_dec=2.29
parallax=7.57
p_error=0.57
absmag_v=−4.11
Starbox detail
age=
metal=20% Sun
mass=10
radius=
rotation=
luminosity= 20,000
temperature=24,750
Starbox catalog
names=Adhara, Adharaz, Undara, ε CMa, 21 CMa, HR 2618, CoD -28°3666, HD 52089, SAO 172676, FK5 268, HIP 33579, GC 9188, ADS 5654, CCDM 06586-2858
Starbox reference
Simbad=HD+52089

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". It is known as 弧矢七 (the Seventh Star of the Bow and Arrow) in Chinese.

Adhara is a binary star, about 430 light years 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 25,000 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.

A few million years ago, Adhara was much closer to the Sun than it is at present, causing it to be a much brighter star in the night sky. About 4,700,000 years ago, Adhara was 34 light years from the Sun, and was the brightest star in the sky with a magnitude of –3.99. No other star has attained this brightness since, nor will any other star attain this brightness for at least five million years. [Sky and Telescope, April 1998.]

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.


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  • Epsilon Canis Majoris — Pour les articles homonymes, voir Epsilon (homonymie). ε Canis Majoris (Adara/Adhara) Données d observation (Époque J2000.0) Ascension droite 06h 58m 37,50s …   Wikipédia en Français

  • Epsilon Canis Majoris — Adhara ist Name des Sterns ε (epsilon) Canis Maioris im Sternbild Großer Hund. Der Name (von arab. عذارى ‘aðāra’) bedeutet (die) Jungfrauen . Er gehört zu den hellen Riesen. Adhara ist ein Doppelsternsystem in 470 Lichtjahren Entfernung. Der… …   Deutsch Wikipedia

  • Canis Majoris — can refer to any of a number of stars which, as seen from Earth, reside within the Canis Major constellation, including:* Sirius (Alpha Canis Majoris), the brightest star in the terrestrial sky * VY Canis Majoris, the largest known star.Also… …   Wikipedia

  • Ε Canis Majoris — Epsilon Canis Majoris ε Canis Majoris (Adara/Adhara) Données d observation (Époque J2000.0) Ascension droite 06h 58m 37,50s Déclinaison 28° 58′ 20,0″ Constellation Grand Chien Magnitude …   Wikipédia en Français

  • Nu² Canis Majoris — For other star systems with this Bayer designation, see Nu Canis Majoris. ν² Canis Majoris Observation data Epoch J2000.0      Equinox J2000.0 Constellation Canis Major Right ascension 06h36m41.0s …   Wikipedia

  • Alpha Canis Majoris — Datenbanklinks zu Sirius (α Canis Majoris) Doppelstern Sirius (α CMa) …   Deutsch Wikipedia

  • Epsilon CMa — Epsilon Canis Majoris ε Canis Majoris (Adara/Adhara) Données d observation (Époque J2000.0) Ascension droite 06h 58m 37,50s Déclinaison 28° 58′ 20,0″ Constellation Grand Chien Magnitude …   Wikipédia en Français

  • Epsilon (homonymie) — Cette page d’homonymie répertorie les différents sujets et articles partageant un même nom. Le mot epsilon peut renvoyer à : Epsilon, lettre grecque ; Epsilon Euskadi, une équipe de course automobile ; Ouragan Epsilon, un… …   Wikipédia en Français

  • Alpha Canis Maioris — Datenbanklinks zu Sirius (α Canis Majoris) Doppelstern Sirius (α CMa) …   Deutsch Wikipedia

  • Adara — Epsilon Canis Majoris ε Canis Majoris (Adara/Adhara) Données d observation (Époque J2000.0) Ascension droite 06h 58m 37,50s Déclinaison 28° 58′ 20,0″ Constellation Grand Chien Magnitude …   Wikipédia en Français


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