Canis Major

Canis Major /ˌkeɪnᵻs ˈmeɪdʒər/ is a constellation in the southern celestial hemisphere. In the second century, it was included in Ptolemy's 48 constellations, and is counted among the 88 modern constellations. Its name is Latin for "greater dog" in contrast to Canis Minor, the "lesser dog"; both figures are commonly represented as following the constellation of Orion the hunter through the sky. The Milky Way passes through Canis Major and several open clusters lie within its borders, most notably M41.

Canis Major contains Sirius, the brightest star in the night sky, known as the "dog star". It is bright because of its proximity to the Solar System. In contrast, the other bright stars of the constellation are stars of great distance and high luminosity. At magnitude 1.5, Epsilon Canis Majoris (Adhara) is the second brightest star of the constellation and the brightest source of extreme ultraviolet radiation in the night sky. Next in brightness are the yellow-white supergiant Delta (Wezen) at 1.8, the blue-white giant Beta (Mirzam) at 2.0, blue-white supergiants Eta (Aludra) at 2.4 and Omicron¹ at 3.0, and white spectroscopic binary Zeta (Furud), also at 3.0. The red hypergiant VY Canis Majoris is one of the largest stars known, while the neutron star RX J0720.4-3125 has a radius of a mere 5 km.

Canis Major Overdensity

The Canis Major Dwarf Galaxy (CMa Dwarf) or Canis Major Overdensity (CMa Overdensity) is a disputed dwarf irregular galaxy in the Local Group, located in the same part of the sky as the constellation Canis Major.

The supposed small galaxy contains a relatively high percentage of red giant stars, and is thought to contain an estimated one billion stars in all.

The Canis Major Dwarf Galaxy is classified as an irregular galaxy and is now thought to be the closest neighbouring galaxy to our location in the Milky Way, being located about 25,000 light-years away from the Solar System and 42,000 light-years from the Galactic Center. It has a roughly elliptical shape and is thought to contain as many stars as the Sagittarius Dwarf Elliptical Galaxy, the previous contender for closest galaxy to our location in the Milky Way.

Discovery

The existence of a strong elliptical-shaped stellar over-density was reported in November 2003 by an international team of French, Italian, British and Australian astronomers, who claimed their study pointed to a newly discovered dwarf galaxy: the Canis Major Dwarf Galaxy. This structure is located closer to the Sun than the center of our Galaxy, at approximately 7 kpc from the Sun.

Canis Major (Chinese astronomy)

According to traditional Chinese uranography, the modern constellation Canis Major is located within the southern quadrant of the sky, which is symbolized as the Vermilion Bird of the South (南方朱雀, Nán Fāng Zhū Què).

The name of the western constellation in modern Chinese is 大犬座 (dà quǎn zuò), meaning "the giant dog constellation".

Stars

See also

References

External links