Kaler, James B. "Omicron-2 Canis Majoris". Stars. University of Illinois . Retrieved 24 February 2014. a b "18 Canis Majoris". SIMBAD Astronomical Database. Centre de Données astronomiques de Strasbourg . Retrieved 18 February 2014. Consolmagno, Guy (2011). Turn Left at Orion: Hundreds of Night Sky Objects to See in a Home Telescope – and How to Find Them. Cambridge, United Kingdom: Cambridge University Press. p.81. ISBN 978-1-139-50373-0. da Silva, L.; Girardi, L.; Pasquini, L.; Setiawan, J.; von der Lühe, O.; de Medeiros, J.R.; Hatzes, A.; Döllinger, M.P.; Weiss, A. (2006). "Basic Physical Parameters of a Selected Sample of Evolved Stars". Astronomy and Astrophysics. 458 (2): 609–23. arXiv: astro-ph/0608160. Bibcode: 2006A&A...458..609D. doi: 10.1051/0004-6361:20065105. S2CID 9341088. Bright stars were important to the ancient Polynesians for navigation of the Pacific Ocean. They also served as latitude markers; the declination of Sirius matches the latitude of the archipelago of Fiji at 17°S and thus passes directly over the islands each sidereal day. [34] Sirius served as the body of a "Great Bird" constellation called Manu, with Canopus as the southern wingtip and Procyon the northern wingtip, which divided the Polynesian night sky into two hemispheres. [35] Just as the appearance of Sirius in the morning sky marked summer in Greece, it marked the onset of winter for the Māori, whose name Takurua described both the star and the season. Its culmination at the winter solstice was marked by celebration in Hawaii, where it was known as Ka'ulua, "Queen of Heaven". Many other Polynesian names have been recorded, including Tau-ua in the Marquesas Islands, Rehua in New Zealand, and Ta'urua-fau-papa "Festivity of original high chiefs" and Ta'urua-e-hiti-i-te-tara-te-feiai "Festivity who rises with prayers and religious ceremonies" in Tahiti. [36] Kinematics [ edit ]

Tomkin, Jocelyn (April 1998). "Once and Future Celestial Kings". Sky and Telescope. 95 (4): 59–63. Bibcode: 1998S&T....95d..59T. Knobel, Edward B. (1895). "Al Achsasi Al Mouakket, on a Catalogue of Stars in the Calendarium of". Monthly Notices of the Royal Astronomical Society. 55 (8): 429–38. Bibcode: 1895MNRAS..55..429K. doi: 10.1093/mnras/55.8.429. The Voyager 2 spacecraft, which was launched in 1977 to study the Jovian planets in our system, will pass within 4.3 light years of Sirius in about 296,000 years – assuming the spacecraft is still around. (One light year is almost 10 trillion kilometres, or 6 trillion miles.) Between these stars and Sirius lie Omicron 1, Omicron 2, and Pi Canis Majoris. Omicron 2 is a massive supergiant star about 21 times as massive as the Sun. [49] Only 7million years old, [49] it has exhausted the supply of hydrogen at its core and is now processing helium. [50] It is an Alpha Cygni variable that undergoes periodic non-radial pulsations, which cause its brightness to cycle from magnitude 2.93 to 3.08 over a 24.44-day interval. [51] Omicron 1 is an orange K-type supergiant of spectral type K2.5Iab that is an irregular variable star, varying between apparent magnitudes 3.78 and 3.99. [52] Around 18 times as massive as the Sun, it shines with 65,000 times its luminosity. [53]Tau Canis Majoris is a Beta Lyrae-type eclipsing multiple star system that varies from magnitude 4.32 to 4.37 over 1.28 days. [71] Its four main component stars are hot O-type stars, with a combined mass 80 times that of the Sun and shining with 500,000 times its luminosity, but little is known of their individual properties. A fifth component, a magnitude 10 star, lies at a distance of 13,000 astronomical units (0.21 ly). The system is only 5million years old. [72] UW Canis Majoris is another Beta Lyrae-type star 3000 light-years from Earth; it is an eclipsing binary that ranges in magnitude from a minimum of 5.3 to a maximum of 4.8. It has a period of 4.4 days; [6] its components are two massive hot blue stars, one a blue supergiant of spectral type O7.5–8 Iab, while its companion is a slightly cooler, less evolved and less luminous supergiant of spectral type O9.7Ib. The stars are 200,000 and 63,000 times as luminous as the Sun. However the fainter star is the more massive at 19 solar masses to the primary's 16. [73] R Canis Majoris is another eclipsing binary that varies from magnitude 5.7 to 6.34 over 1.13 days, [74] with a third star orbiting these two every 93 years. The shortness of the orbital period and the low ratio between the two main components make this an unusual Algol-type system. [75] With an apparent magnitude of −1.46, Sirius is the brightest star in the night sky, almost twice as bright as the second-brightest star, Canopus. [71] From Earth, Sirius always appears dimmer than Jupiter and Venus, and at certain times also dimmer than Mercury and Mars. [72] Sirius is visible from almost everywhere on Earth, except latitudes north of 73°N, and it does not rise very high when viewed from some northern cities (reaching only 13°above the horizon from Saint Petersburg). [73] Because of its declination of roughly −17°, Sirius is a circumpolar star from latitudes south of 73°S. From the Southern Hemisphere in early July, Sirius can be seen in both the evening where it sets after the Sun and in the morning where it rises before the Sun. [74] Along with Procyon and Betelgeuse, Sirius forms one of the three vertices of the Winter Triangle to observers in the Northern Hemisphere. [75]

The brightest star seen from Earth, Sirius is recorded in some of the earliest astronomical records. Its displacement from the ecliptic causes its heliacal rising to be remarkably regular compared to other stars, with a period of almost exactly 365.25days holding it constant relative to the solar year. This rising occurs at Cairo on 19July ( Julian), placing it just before the onset of the annual flooding of the Nile during antiquity. [28] Owing to the flood's own irregularity, the extreme precision of the star's return made it important to the ancient Egyptians, [28] who worshipped it as the goddess Sopdet ( Ancient Egyptian: Spdt, "Triangle"; [a] Greek: Σῶθις}, Sō̂this), guarantor of the fertility of their land. [b] Epsilon Canis Majoris – Double Star". SIMBAD Astronomical Database. Centre de Données astronomiques de Strasbourg . Retrieved 16 February 2014. Kaler, James B. "Omicron1 Canis Majoris". Stars. University of Illinois . Retrieved 24 February 2014. Sirius, also known as the Dog Star, α Canis Majoris (Alpha Canis Majoris), or Canicula, is the brightest star in the night sky. It lies at a distance of 8.60 light years (2.64 parsecs) from Earth, in the constellation Canis Major, the Greater Dog. Sirius is not the brightest star because it is more luminous than other visible stars, but because it is located so close to the solar system. It is the fifth closest star system to Earth and contains two of the eight nearest stars to Earth. In 1915, Walter Sydney Adams, using a 60-inch (1.5m) reflector at Mount Wilson Observatory, observed the spectrum of SiriusB and determined that it was a faint whitish star. [53] This led astronomers to conclude that it was a white dwarf—the second to be discovered. [54] The diameter of SiriusA was first measured by Robert Hanbury Brown and Richard Q. Twiss in 1959 at Jodrell Bank using their stellar intensity interferometer. [55] In 2005, using the Hubble Space Telescope, astronomers determined that SiriusB has nearly the diameter of the Earth, 12,000 kilometres (7,500mi), with a mass 102% of the Sun's. [56] Colour controversy [ edit ] Twinkling of Sirius ( apparent magnitude = −1.5) in the evening shortly before upper culmination on the southern meridian at a height of 20degrees above the horizon. During 29 seconds Sirius moves on an arc of 7.5 minutes from the left to the right.A dreamy, postapocalyptic love letter to things of beauty, big and small: a twitching trout, a can of Sprite, empathy, sex, decency, and a good dog” Epsilon, Omicron 2, Delta, and Eta Canis Majoris were called Al Adzari "the virgins" in medieval Arabic tradition. [38] Marking the dog's right thigh on Bayer's atlas is Epsilon Canis Majoris, [33] also known as Adhara. At magnitude 1.5, it is the second-brightest star in Canis Major and the 23rd-brightest star in the sky. It is a blue-white supergiant of spectral type B2Iab, around 404 light-years from Earth. [39] This star is one of the brightest known extreme ultraviolet sources in the sky. [40] It is a binary star; the secondary is of magnitude 7.4. Its traditional name means "the virgins", having been transferred from the group of stars to Epsilon alone. [41] Nearby is Delta Canis Majoris, also called Wezen. It is a yellow-white supergiant of spectral type F8Iab and magnitude 1.84, around 1605 light-years from Earth. [42] With a traditional name meaning "the weight", Wezen is 17 times as massive and 50,000 times as luminous as the Sun. If located in the centre of the Solar System, it would extend out to Earth as its diameter is 200 times that of the Sun. Only around 10million years old, Wezen has stopped fusing hydrogen in its core. Its outer envelope is beginning to expand and cool, and in the next 100,000 years it will become a red supergiant as its core fuses heavier and heavier elements. Once it has a core of iron, it will collapse and explode as a supernova. [43] Nestled between Adhara and Wezen lies Sigma Canis Majoris, known as Unurgunite to the Boorong and Wotjobaluk people, [23] a red supergiant of spectral type K7Ib that varies irregularly between magnitudes 3.43 and 3.51. [44] a b Hamacher, Duane W.; Frew, David J. (2010). "An Aboriginal Australian Record of the Great Eruption of Eta Carinae". Journal of Astronomical History & Heritage. 13 (3): 220–34. arXiv: 1010.4610. Bibcode: 2010JAHH...13..220H. doi: 10.3724/SP.J.1440-2807.2010.03.06. S2CID 118454721. Sirius is colloquially known as the " Dog Star", reflecting its prominence in its constellation, Canis Major (the Greater Dog). [19] The heliacal rising of Sirius marked the flooding of the Nile in Ancient Egypt and the " dog days" of summer for the ancient Greeks, while to the Polynesians, mostly in the Southern Hemisphere, the star marked winter and was an important reference for their navigation around the Pacific Ocean.