Nu² Canis Majoris (ν² Canis Majoris) is a single

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

in the southern

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

Canis Major Canis Major is a constellation in the Southern Celestial Hemisphere, 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 fo ...

. It is a cool

giant In folklore, giants (from Ancient Greek: '' gigas'', cognate giga-) are beings of human-like appearance, but are at times prodigious in size and strength or bear an otherwise notable appearance. The word ''giant'' is first attested in 1297 fr ...

with two confirmed

exoplanet An exoplanet or extrasolar planet is a planet outside the Solar System. The first possible evidence of an exoplanet was noted in 1917 but was not recognized as such. The first confirmation of detection occurred in 1992. A different planet, init ...

Characteristics

With an

apparent visual magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's lig ...

of 3.96, it is bright enough to be seen with the naked eye to the southwest of

Sirius Sirius is the list of brightest stars, brightest star in the night sky. Its name is derived from the Ancient Greek language, Greek word , or , meaning 'glowing' or 'scorching'. The star is designated α Canis Majoris, Latinisation ...

. It has an annual parallax shift of around 50.63

mas Mas, Más or MAS may refer to: Film and TV * Más y Menos, fictional superhero characters, from the Teen Titans animated television series * Más (Breaking Bad), "Más" (''Breaking Bad''), a season three episode of ''Breaking Bad'' Songs * Más ( ...

as seen from Earth, thus this system is about 64.4

light year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

s from the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

, a parallax well within the error margins of the figure later given by the Gaia space observatory data release 2, namely 50.471 ± 0.4168. It is an evolved

K-type giant A giant star is a star with substantially larger radius and luminosity than a main-sequence (or ''dwarf'') star of the same surface temperature.Giant star, entry in ''Astronomy Encyclopedia'', ed. Patrick Moore, New York: Oxford University Pre ...

around 4.6 billion years old. Around 1.3 times as massive as the Sun, it has expanded to around 4.9 times the Sun's diameter and 11 times its luminosity. In 2011, it was found to have a planet.

Chinese name

Chinese astronomy Astronomy in China has a long history stretching from the Shang dynasty, being refined over a period of more than 3,000 years. The ancient Chinese people have identified stars from 1300 BCE, as Chinese star names later categorized in the twe ...

, ν² Canis Majoris is called 野雞,

Pinyin Hanyu Pinyin (), often shortened to just pinyin, is the official romanization system for Standard Mandarin Chinese in China, and to some extent, in Singapore and Malaysia. It is often used to teach Mandarin, normally written in Chinese for ...

: Yějī, meaning ''Wild Cockerel'', because this star is marking itself and stand alone in ''Wild Cockerel'' asterism,

Well A well is an excavation or structure created in the ground by digging, driving, or drilling to access liquid resources, usually water. The oldest and most common kind of well is a water well, to access groundwater in underground aquifers. The ...

mansion (see :

Chinese constellation Traditional Chinese astronomy has a system of dividing the celestial sphere into asterisms or constellations, known as "officials" (Chinese ''xīng guān''). The Chinese asterisms are generally smaller than the constellations of Hellenistic t ...

). 野雞 (Yějī), westernized into Ya Ke. According to R.H. Allen opinion, the name ''Ya Ke'' is asterism consisting ο¹ Canis Majoris and π Canis Majoris, with other small stars in the body of the DogRichard Hinckley Allen: Star Names — Their Lore and Meaning: Canis Major
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Planetary system

By measuring periodic variations in the

radial velocity The radial velocity or line-of-sight velocity, also known as radial speed or range rate, of a target with respect to an observer is the temporal rate of change, rate of change of the distance or Slant range, range between the two points. It is e ...

of the host star between 2009 and 2010, the Pan-Pacific Planet Search program was able to identify a planet orbiting Nu² Canis Majoris. An orbital fit produced a minimum mass estimate of with an

orbital period The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets ...

of 2.1 years and an

eccentricity Eccentricity or eccentric may refer to: * Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal" Mathematics, science and technology Mathematics * Off-center, in geometry * Eccentricity (graph theory) of a v ...

of 0.23. Star spots were ruled out as a source for the signal with a false-alarm probability of 98.7%. Further observations through 2019 detected the planet, as well as a secondary planet c in a 4:3

orbital resonance In celestial mechanics, orbital resonance occurs when orbiting bodies exert regular, periodic gravitational influence on each other, usually because their orbital periods are related by a ratio of small integers. Most commonly, this relationsh ...

with planet b.

References

External links

Spectrophotometric data for the star
{{DEFAULTSORT:Nu2 Canis Majoris Canis Major Canis Majoris, Nu2 K-type giants Planetary systems with two confirmed planets Canis Majoris, 07 031592 2429 047205 Durchmusterung objects 0239.1