Canis minor

Canis Minor, in Spanish Can Menor (the small dog) is one of the 88 modern constellations. It was also evidently part of the 48 primitive constellations of Ptolemy's Almagest, data that is included in the source of this last work, the great work called Astronomical by Manilius of Antioch. The figure of the Canis Minor is simple: a line joining two stars. Procyon, its brightest star, forms together with Betelgeuse (Orion) and Sirius (Canis Major) the "Winter Triangle".

Notable features

Constellation of Canis Minoris

The brightest star in Canis Minor, Procyon (α Canis Minoris), lies only 11.4 light-years from the solar system. It is a binary system whose main component is a white-yellow star of the spectral type F5IV-V seven times more luminous than the Sun, which indicates its status as a subgiant that is finishing fusing the hydrogen in its nucleus and has begun to expand. It is accompanied by a DQZ-type white dwarf whose orbital period is 40.8 years.

The second brightest star, β Canis Minoris, is called Gomeisa. It is a hot bluish-white star of spectral type B8Ve with an effective temperature of 11,500 K, 250 times more luminous than the Sun It is a Be star —surrounded by a disk of matter that emits radiation— slightly variable. Next in brightness is γ Canis Minoris, an orange giant and spectroscopic binary. The fourth brightest star in Canis Minor has no Bayer designation: HD 66141 is also an orange giant around which a planet with a mass at least six times that of Jupiter has been discovered.

Another star in the constellation, ε Canis Minoris, is a luminous giant of type G6.5IIb with a bolometric luminosity 1174 times greater than solar luminosity. It is also considered a barium star, whose spectrum is characterized by the presence of ionized barium. ζ Canis Minoris is also a luminous giant, although much hotter—spectral type B8II—and is a mercury-manganese star, with an overabundance of elements such as mercury, manganese, neon, and phosphorus.

Among the constellation's variables is R Canis Minoris, an S-type star and Mira variable whose apparent magnitude fluctuates between +7.0 and +12.0 over a 340-day period.

Luyten's Star is a red dwarf of spectral type M3.5V distant 12.4 light years from Earth. It has two planets that orbit at 0.036 and 0.091 AU from the star. The outermost, in the habitable zone, is a "super-Earth" with a mass of 2.89 ± 0.26 Earth masses. In October 2017, a series of radio signals were transmitted to this planet as part of a project of METI and the Sónar music festival.

Although the Milky Way traverses much of Canis Minor, there are few deep-sky objects in the constellation. Among them is NGC 2485, a barred spiral galaxy about 210 million light-years away.

Main Stars

Orbit of the two components of Procyon

• α Canis Minoris (Procyon), the eighth most brilliant star of the sky, has magnitude 0.36. Its distance to the solar system is approximately 11 light years. It is accompanied by a faint white dwarf, Procyon B, of magnitude 13.
• β Canis Minoris (Gomeisa), white-azulada star of magnitude 2,89 with a material disk around; it is also a Gamma Cassiopeiae variable.
• γ Canis Minoris, orange giant of magnitude 4,33 and spectroscopic binary.
• δ Canis Minoris, name shared by three different stars: δ¹ CMi, δ² CMi and δ³ CMi. δ1 Canis Minoris is a white-yellow giant 760 light years away and δ2 Canis Minoris is a star of the main sequence.
• ε Canis Minoris, bright yellow giant of magnitude 4,99.
• ج Canis Minoris, a bright white-azulada giant of magnitude 5,13; it is a mercury-manganese star.
• Cristian Canis Minoris, of magnitude 5,24, also white-yellow giant.
• 14 Canis Minoris, an orange giant of magnitude 5.30.
• R Canis Minoris, variable star Mira and type S star.
• U Canis Minoris, variable Mira whose brightness varies between magnitude 7.3 and 11.0 in a period of 338 days.
• YZ Canis Minoris (Gliese 285), red dwarf that is at the same time shining and variable star BY Draconis; it is 19.3 light years from the solar system.
• Luyten Star (Gliese 273), red dwarf only 12,37 light years away. In 2017 two extra-solar planets were discovered orbiting this star and in 2019 it was announced that the planetary system could have two additional planets.

Deep Sky Objects

NGC 2485 (Credits: Sloan Digital Sky Survey)

• NGC 2485, galaxy that is located 3.5 to the NE of the bright Procyon.

Mythology

The Minor Can in the Uranographia of Johann Bode.

Eratosthenes identified Canis Minor with the dog of Orion, registered at the same time as his master since he had always been in all his adventures. But, like the Greater Dog, it also records the variant that it may be the dog Mera, who with her lamentations because of having found the corpses of her masters Icario and Erigone, attracted people to show them they gave burial Another variant is that it would be the dog of Céfalo that tried to hunt the fox of Teumeso.

The brightest star in this constellation is named after Procyon which means "before the dog" in reference to its appearance immediately before the dog star (Sirius).

Medieval Arab astronomers upheld the depiction of Canis Minor (al-Kalb al-Asghar in Arabic) as a dog; in his Book of Fixed Stars, Abd al-Rahman al-Sufi included a diagram of the constellation with a superimposed canine figure. There was a slight difference between the Ptolemaic view of Canis Minor and the Arabic one; al-Sufi claims Mirzam, now assigned to Orion, as part of both Canis Minor - the dog's collar - and his modern home. The Arabic names of Procyon and Gomeisa alluded to their proximity and resemblance to Sirius, although they were not direct translations from the Greek; Procyon was called ash-Shi'ra ash-Shamiya, the "Sirio syria" and Gomeisa was called ash-Shira al-Ghamisa, the dark-eyed Syrian. In the Merazig of Tunisia, shepherds observe six constellations that mark the passing of the hot dry season. One of them, called Merzem, includes the stars of Canis Minor and Canis Major and is the herald of two weeks of hot weather.

The ancient Egyptians considered this constellation Anubis, the jackal god.

Canis Minor constellation can be seen next to Monoceros and obsolete constellation Atelier Typographique on this star map of 1825 Urania's Mirror'

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Alternative names have been proposed: Johann Bayer in the early 17th century named the constellation Fovea "The Moat", and Morus "Sicomino Tree". The 17th century German poet and writer Philippus Caesius related it to Tobias's dog from the Apocrypha. Richard A. Proctor gave the constellation the name Felis "the Cat" in 1870 (in contrast to Canis Major, which he had abbreviated to Canis "the Dog"), explaining that he sought to shorten the names of the constellations to make them more manageable on Sky Charts. Canis Minor is sometimes confused with Canis Major and given the name Canis Orionis ("Dog of Orion").

In non-western astronomy

In Chinese astronomy, the stars corresponding to Canis Minor are found in the Vermilion Bird of the South (南方朱雀, Nán Fāng Zhū Què). Procyon, Gomeisa, and Eta Canis Minoris form an asterism known as Nánhé, the River of the South. With its counterpart, the Beihe River of the North (Castor and Pollux), Nánhé was also associated with a gate or sentinel. Together with Zeta and 8 Cancri, 6 Canis Minoris and 11 Canis Minoris it formed the asterism Shuiwei, which literally means "water level". Combined with additional stars in Gemini, Shuiwei represented an official who managed flood waters or a water level marker. Neighboring Korea recognized four stars in Canis Minor as part of a different constellation, "the position of the water". This constellation was located in the Red Bird, the southern portion of the sky.

Polynesian peoples often did not recognize Canis Minor as a constellation, but they saw Procyon as significant and often named it; in the Tuamotu Archipelago it was known as Hiro, meaning "twisted like a coconut fiber thread", and Kopu-nui-o-Hiro ("Hiro's big belly"), which was either a name for the modern figure of Canis Minor or an alternate name for Procyon. Other names included Vena (after a goddess), in Mangaia, and Puanga-hori (false Puanga, the name of Rigel), in New Zealand. In the Society Islands, Procyon was called Ana-tahua-vahine-o-toa-te-manava, literally "Aster the brave-hearted priestess", figuratively the &# 34;pillar for elocution". The Wardaman people of the Northern Territory in Australia gave Procyon and Gomeisa the names Magum and Gurumana, describing them as human that were transformed into Eucalyptus in the Dream Time. Although their skin had turned to bark, they were able to speak in a human voice by waving their leaves.

The Aztec calendar was related to their cosmology. The stars of Canis Minor were incorporated along with some stars of Orion and Gemini in an asterism associated with the day called "Water".