Eta Canis Majoris
Encyclopedia
Eta Canis Majoris (η CMa, η Canis Majoris) is a star in the constellation
Canis Major
. It has the traditional name Aludra.
The name Aludra originates from the Arabic
: عذرا al-‘aðrā "the virgin". This star, along with ε CMa
(Adhara), δ CMa
(Wezen) and ο2 CMa
(Thanih al Adzari), were Al ʽAdhārā (ألعذاري), the Virgins.
In Chinese
, , meaning Bow and Arrow
, refers to an asterism consisting of η Canis Majoris, δ Canis Majoris
, c Puppis, ZI 674, ο Puppis, κ Puppis, ε Canis Majoris
, κ Canis Majoris
and π Puppis
. Consequently, δ Canis Majoris itself is known as
due to being intrinsically many times brighter (absolute magnitude
) than the Sun
. A blue supergiant
, Aludra has only been around a fraction of the time our Sun has, yet is already in the last stages of its life. It is still expanding and may become a red supergiant, or perhaps has already passed that phase, but in either case it will become a supernova
within the next few million years.
η Canis Majoris is classified as an Alpha Cygni type
variable star
and its brightness varies from magnitude +2.38 to +2.48.
and USS Aludra (AK-72)
, a Crater class cargo ship
, were United States Navy
vessels named after the constellation.
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
Canis Major
Canis Major
Canis Major is one of the 88 modern constellations, and was included in the 2nd-century astronomer Ptolemy's 48 constellations. Its name is Latin for 'greater dog', and is commonly represented as one of the dogs following Orion the hunter...
. It has the traditional name Aludra.
The name Aludra originates from the Arabic
Arabic language
Arabic is a name applied to the descendants of the Classical Arabic language of the 6th century AD, used most prominently in the Quran, the Islamic Holy Book...
: عذرا al-‘aðrā "the virgin". This star, along with ε CMa
Epsilon Canis Majoris
Epsilon Canis Majoris is the second brightest star in the constellation Canis Major, and one of the brightest stars in the night sky. It has the Bayer designation "epsilon" despite being the second brightest and not the fifth brightest star in its constellation. It has the traditional name Adhara...
(Adhara), δ CMa
Delta Canis Majoris
Delta Canis Majoris is a star in the constellation Canis Major. It has the traditional name Wezen or Wesen...
(Wezen) and ο2 CMa
Omicron2 Canis Majoris
Omicron2 Canis Majoris is a star in the constellation Canis Major. It is one of the most luminous stars known, a supergiant that has used up the hydrogen fuel in its core and has entered the evolutionary stage where it is fusing helium atoms to form carbon...
(Thanih al Adzari), were Al ʽAdhārā (ألعذاري), the Virgins.
In Chinese
Chinese language
The Chinese language is a language or language family consisting of varieties which are mutually intelligible to varying degrees. Originally the indigenous languages spoken by the Han Chinese in China, it forms one of the branches of Sino-Tibetan family of languages...
, , meaning Bow and Arrow
Well (Chinese constellation)
The Well mansion is one of the Twenty-eight mansions of the Chinese constellations. It is one of the southern mansions of the Vermilion Bird.-Asterisms:...
, refers to an asterism consisting of η Canis Majoris, δ Canis Majoris
Delta Canis Majoris
Delta Canis Majoris is a star in the constellation Canis Major. It has the traditional name Wezen or Wesen...
, c Puppis, ZI 674, ο Puppis, κ Puppis, ε Canis Majoris
Epsilon Canis Majoris
Epsilon Canis Majoris is the second brightest star in the constellation Canis Major, and one of the brightest stars in the night sky. It has the Bayer designation "epsilon" despite being the second brightest and not the fifth brightest star in its constellation. It has the traditional name Adhara...
, κ Canis Majoris
Kappa Canis Majoris
Kappa Canis Majoris is a star in the constellation Canis Major.κ Canis Majoris is a blue-white B-type subgiant with a mean apparent magnitude of +3.50. It is approximately 790 light years from Earth. It is classified as a Gamma Cassiopeiae type variable star and its brightness varies from...
and π Puppis
Pi Puppis
Pi Puppis is a star in the constellation Puppis.In Chinese, , meaning Bow and Arrow, refers to an asterism consisting of π Puppis, δ Canis Majoris, η Canis Majoris, c Puppis, ZI 674, ο Puppis, κ Puppis, ε Canis Majoris and κ Canis Majoris...
. Consequently, δ Canis Majoris itself is known as
Properties
Aludra shines brightly in the skies in spite of a large distance from EarthEarth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
due to being intrinsically many times brighter (absolute magnitude
Absolute magnitude
Absolute magnitude is the measure of a celestial object's intrinsic brightness. it is also the apparent magnitude a star would have if it were 32.6 light years away from Earth...
) than the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
. A blue supergiant
Supergiant
Supergiants are among the most massive stars. They occupy the top region of the Hertzsprung-Russell diagram. In the Yerkes spectral classification, supergiants are class Ia or Ib . They typically have bolometric absolute magnitudes between -5 and -12...
, Aludra has only been around a fraction of the time our Sun has, yet is already in the last stages of its life. It is still expanding and may become a red supergiant, or perhaps has already passed that phase, but in either case it will become a supernova
Supernova
A supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months...
within the next few million years.
η Canis Majoris is classified as an Alpha Cygni type
Alpha Cygni variable
Alpha Cygni variables are variable stars which exhibit non-radial pulsations, meaning that some portions of the stellar surface are contracting at the same time others parts expand. They are supergiant stars of spectral types B or A...
variable star
Variable star
A star is classified as variable if its apparent magnitude as seen from Earth changes over time, whether the changes are due to variations in the star's actual luminosity, or to variations in the amount of the star's light that is blocked from reaching Earth...
and its brightness varies from magnitude +2.38 to +2.48.
Namesakes
Both USS Aludra (AF-55)USS Aludra (AF-55)
USS Aludra was an Alstede-class stores ship acquired by the U.S. Navy. Her task was to carry stores, refrigerated items, and equipment to ships in the fleet, and to remote stations and staging areas....
and USS Aludra (AK-72)
USS Aludra (AK-72)
The USS Aludra was a Crater-class cargo ship in the service of the United States Navy in World War II. Named after the star Aludra in the constellation Canis Major, it was the first ship of the Navy to bear this name....
, a Crater class cargo ship
Crater class cargo ship
Crater-class cargo ship is a category of freighter that was constructed for use by the United States Navy during World War II under Maritime Commission EC2-S-C1 type....
, were United States Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
vessels named after the constellation.