Cetus () is a

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 ...

, sometimes called 'the

whale Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...

' in English. The

Cetus Cetus () is a constellation, sometimes called 'the whale' in English. The Cetus (mythology), Cetus was a sea monster in Greek mythology which both Perseus and Heracles needed to slay. Cetus is in the region of the sky that contains other water- ...

was a

sea monster Sea monsters are beings from folklore believed to dwell in the sea and often imagined to be of immense size. Marine monsters can take many forms, including sea dragons, sea serpents, or tentacled beasts. They can be slimy and scaly and are ofte ...

Greek mythology A major branch of classical mythology, Greek mythology is the body of myths originally told by the Ancient Greece, ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the Cosmogony, origin and Cosmology#Metaphysical co ...

which both

Perseus In Greek mythology, Perseus (Help:IPA/English, /ˈpɜːrsiəs, -sjuːs/; Greek language, Greek: Περσεύς, Romanization of Greek, translit. Perseús) is the legendary founder of Mycenae and of the Perseid dynasty. He was, alongside Cadmus ...

and

Heracles Heracles ( ; grc-gre, Ἡρακλῆς, , glory/fame of Hera), born Alcaeus (, ''Alkaios'') or Alcides (, ''Alkeidēs''), was a divine hero in Greek mythology, the son of Zeus and Alcmene, and the foster son of Amphitryon.By his adoptive ...

needed to slay. Cetus is in the region of the sky that contains other water-related constellations:

Aquarius Aquarius may refer to: Astrology * Aquarius (astrology), an astrological sign * Age of Aquarius, a time period in the cycle of astrological ages Astronomy * Aquarius (constellation) * Aquarius in Chinese astronomy Arts and entertainme ...

Pisces Pisces may refer to: * Pisces, an obsolete (because of land vertebrates) taxonomic superclass including all fish * Pisces (astrology), an astrological sign * Pisces (constellation), a constellation **Pisces Overdensity, an overdensity of stars in ...

and Eridanus.

Features

Ecliptic

Cetus is not among the 12 true

zodiac The zodiac is a belt-shaped region of the sky that extends approximately 8° north or south (as measured in celestial latitude) of the ecliptic, the Sun path, apparent path of the Sun across the celestial sphere over the course of the year. ...

constellations in the J2000 epoch, nor classical 12-part zodiac. The

ecliptic The ecliptic or ecliptic plane is the orbital plane of the Earth around the Sun. From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic again ...

passes less than 0.25° from one of its corners. Thus the moon and planets will enter Cetus (occulting any stars as a foreground object) in 50% of their successive orbits briefly and the southern part of the sun appears in Cetus for about one day each year. Many asteroids in belts have longer phases occulting the north-western part of Cetus, those with a slightly greater

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a Plane of reference, reference plane and the orbital plane or Axis of rotation, axis of direction of the orbiting object ...

to the ecliptic than the moon and planets. As seen from Mars, the ecliptic (apparent plane of the sun and also the average plane of the planets which is almost the same) passes into it.

Stars

Mira Mira (), designation Omicron Ceti (ο Ceti, abbreviated Omicron Cet, ο Cet), is a red-giant star estimated to be 200–400 light-years from the Sun in the constellation Cetus. ο Ceti is a binary stellar system, consisting of a varia ...

("wonderful", named by Bayer:

Omicron Ceti Mira (), designation Omicron Ceti (ο Ceti, abbreviated Omicron Cet, ο Cet), is a red-giant star estimated to be 200–400 light-years from the Sun in the constellation Cetus. ο Ceti is a Binary star, binary stellar system, consistin ...

, a star of the neck of the asterism) was the first

variable star A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as ...

to be discovered and the prototype of its class, Mira variables. Over a period of 332 days, it reaches a maximum

apparent 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 li ...

of 3 - visible to the naked eye - and dips to a minimum magnitude of 10, invisible to the unaided eye. Its seeming appearance and disappearance gave it its name. Mira pulsates with a minimum size of 400 solar diameters and a maximum size of 500 solar diameters. 420 light-years from Earth, it was discovered by

David Fabricius David Fabricius (9 March 1564 – 7 May 1617) was a German pastor who made two major discoveries in the early days of telescopic astronomy, jointly with his eldest son, Johannes Fabricius (1587–1615). David Fabricius (Latinization of his proper n ...

in 1596. α Ceti, traditionally called Menkar ("the nose"), is a red-hued giant star of magnitude 2.5, 220 light-years from Earth. It is a wide

double star In observational astronomy, a double star or visual double is a pair of stars that appear close to each other as viewed from Earth, especially with the aid of optical telescopes. This occurs because the pair either forms a binary star (i.e. a bi ...

; the secondary is

93 Ceti 93 may refer to: * 93 (number) * one of the years 93 BC, AD 93, 1993, 2093, etc. * 93 Seine-Saint-Denis, French department, Paris, Île-de-France * Atomic number 93: neptunium * ''Ninety-Three'', English title of ''Quatrevingt-treize'' (same meanin ...

, a blue-white hued star of magnitude 5.6, 440 light-years away. β Ceti, also called Deneb Kaitos and Diphda is the brightest star in Cetus. It is an orange-hued giant star of magnitude 2.0, 96 light-years from Earth. The traditional name "Deneb Kaitos" means "the whale's tail". γ Ceti, Kaffaljidhma ("head of the whale") is a very close double star. The primary is a yellow-hued star of magnitude 3.5, 82 light-years from Earth, and the secondary is a blue-hued star of magnitude 6.6.

Tau Ceti Tau Ceti, Latinized from τ Ceti, is a single star in the constellation Cetus that is spectrally similar to the Sun, although it has only about 78% of the Sun's mass. At a distance of just under from the Solar System, it is a relativ ...

is noted for being a near Sun-like star at a distance of 11.9 light-years. It is a yellow-hued

main-sequence star In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hert ...

of magnitude 3.5.

AA Ceti AA, Aa, Double A, or Double-A may refer to: Arts, entertainment and media * ''America's Army'', a 2002 computer game published by the U.S. Army * ''Ancient Anguish'', a computer game in existence since 1992 * Aa!, a J-Pop musical group * Doubl ...

is a triple star system; the brightest member has a magnitude of 6.2. The primary and secondary are separated by 8.4 arcseconds at an angle of 304 degrees. The tertiary is not visible in telescopes. AA Ceti is an eclipsing variable star; the tertiary star passes in front of the primary and causes the system's apparent magnitude to decrease by 0.5 magnitudes.

UV Ceti Luyten 726-8, also known as Gliese 65, is a binary star system that is one of Earth's nearest neighbors, at about 8.7 light years from Earth in the constellation Cetus. The two component stars are both flare stars with the variable st ...

is an unusual binary variable star. 8.7 light-years from Earth, the system consists of two

red dwarfs ''Red Dwarf'' is a British science fiction comedy franchise created by Rob Grant and Doug Naylor, which primarily consists of a television sitcom that aired on BBC Two between 1988 and 1999, and on Dave since 2009, gaining a cult following. T ...

. Both of magnitude 13. One of the stars is a

flare star A flare star is a variable star that can undergo unpredictable dramatic increases in brightness for a few minutes. It is believed that the flares on flare stars are analogous to solar flares in that they are due to the magnetic energy stored in th ...

, which are prone to sudden, random outbursts that last several minutes; these increase the pair's apparent brightness significantly - as high as magnitude 7.

Deep-sky objects

Cetus lies far from the

galactic plane The galactic plane is the plane on which the majority of a disk-shaped galaxy's mass lies. The directions perpendicular to the galactic plane point to the galactic poles. In actual usage, the terms ''galactic plane'' and ''galactic poles'' usuall ...

, so that many distant

galaxies A galaxy is a system of stars, stellar remnants, interstellar gas, dust, dark matter, bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. ...

are visible, unobscured by dust from the

Milky Way The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye ...

. Of these, the brightest is

Messier 77 Messier 77 or M77, also known as NGC 1068 and the Squid Galaxy, is a barred spiral galaxy about 47 million light-years away in the constellation Cetus. Messier 77 was discovered by Pierre Méchain in 1780, who originally described it as a nebul ...

(NGC 1068), a 9th magnitude

spiral galaxy Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''Delta Ceti Delta Ceti, Latinized from δ Ceti, is a single, blue-white hued star in the equatorial constellation of Cetus. The star's apparent visual magnitude of +4.06 means it is near to the cusp of the faintest third of the stars that are visibl ...

. It appears face-on and has a clearly visible nucleus of magnitude 10. About 50 million light-years from Earth, M77 is also a

Seyfert galaxy Seyfert galaxies are one of the two largest groups of active galaxies, along with quasars. They have quasar-like nuclei (very luminous, distant and bright sources of electromagnetic radiation) with very high surface brightnesses whose spectra ...

and thus a bright object in the

radio spectrum The radio spectrum is the part of the electromagnetic spectrum with frequencies from 0 Hz to 3,000 GHz (3 THz). Electromagnetic waves in this frequency range, called radio waves, are widely used in modern technology, particula ...

. Recently, the galactic cluster JKCS 041 was confirmed to be the most distant

cluster of galaxies A galaxy cluster, or a cluster of galaxies, is a structure that consists of anywhere from hundreds to thousands of galaxies that are bound together by gravity, with typical masses ranging from 1014 to 1015 solar masses. They are the second-lar ...

yet discovered. The massive

cD galaxy The type-cD galaxy (also cD-type galaxy, cD galaxy) is a galaxy morphology classification, a subtype of type-D galaxy, type-D Elliptical galaxy#Sizes and shapes, giant elliptical galaxy. Characterized by a large galactic halo, halo of stars, they ...

Holmberg 15A is also found in Cetus. As is spiral galaxy NGC 1042 and ultra-diffuse galaxy

NGC 1052-DF2 NGC 1052-DF2 is an ultra diffuse galaxy (UDG) in the constellation Cetus (constellation), Cetus, which was identified in a wide-field imaging survey of the NGC 1052 group by the Dragonfly Telephoto Array. It has been proposed that the galaxy cont ...

. IC 1613 (

Caldwell Caldwell may refer to: People * Caldwell (surname) * Caldwell (given name) * Caldwell First Nation, a federally recognized Indian band in southern Ontario, Canada Places Great Britain * Caldwell, Derbyshire, a hamlet * Caldwell, East ...

51) is an irregular

dwarf galaxy A dwarf galaxy is a small galaxy composed of about 1000 up to several billion stars, as compared to the Milky Way's 200–400 billion stars. The Large Magellanic Cloud, which closely orbits the Milky Way and contains over 30 billion stars, is ...

near the star 26 Ceti and is a member of the Local Group.

NGC 246 NGC 246 (also known as the Skull Nebula"The Night Sky", ''Astronomy Now'', Oct 2008. or Caldwell 56) is a planetary nebula in the constellation Cetus. It is the first known planetary nebula to have a hierarchical triple star system at its center ...

(Caldwell 56), also called the Cetus Ring, is a

planetary nebula A planetary nebula (PN, plural PNe) is a type of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives. The term "planetary nebula" is a misnomer because they are unrelated to ...

with a magnitude of 8.0, 1600 light-years from Earth. Among some amateur astronomers, NGC 246 has garnered the nickname "Pac-Man Nebula" because of the arrangement of its central stars and the surrounding star field. The Wolf–Lundmark–Melotte (WLM) is a barred irregular galaxy discovered in 1909 by Max Wolf, located on the outer edges of the Local Group. The discovery of the nature of the galaxy was accredited to Knut Lundmark and Philibert Jacques Melotte in 1926. It is in the constellation Cetus.

History and mythology

Cetus may have originally been associated with a

, which would have had mythic status amongst Mesopotamian cultures. It is often now called the Whale, though it is most strongly associated with Cetus the sea-monster, who was slain by

as he saved the princess Andromeda from

Poseidon Poseidon (; grc-gre, Ποσειδῶν) was one of the Twelve Olympians in ancient Greek religion and myth, god of the sea, storms, earthquakes and horses.Burkert 1985pp. 136–139 In pre-Olympian Bronze Age Greece, he was venerated as a ch ...

's wrath. It is in the middle of "The Sea" recognised by mythologists, a set of water-associated constellations, its other members being Eridanus,

Piscis Austrinus Piscis Austrinus is a constellation in the southern celestial hemisphere. The name is Latin for "the southern fish", in contrast with the larger constellation Pisces, which represents a pair of fish. Before the 20th century, it was also known as ...

and

. Cetus has been depicted in many ways throughout its history. In the 17th century, Cetus was depicted as a "dragon fish" by

Johann Bayer Johann Bayer (1572 – 7 March 1625) was a German lawyer and uranographer (celestial cartographer). He was born in Rain, Lower Bavaria, in 1572. At twenty, in 1592 he began his study of philosophy and law at the University of Ingolstadt, a ...

. Both

Willem Blaeu Willem Janszoon Blaeu (; 157121 October 1638), also abbreviated to Willem Jansz. Blaeu, was a Dutch cartographer, atlas maker and publisher. Along with his son Johannes Blaeu, Willem is considered one of the notable figures of the Netherlandis ...

and

Andreas Cellarius Andreas Cellarius (–1665) was a Dutch–German cartographer and cosmographer best known for his 1660 ''Harmonia Macrocosmica'', a major star atlas. Life He was born in Neuhausen, and was educated in Heidelberg. The Protestant Cellarius m ...

depicted Cetus as a whale-like creature in the same century. However, Cetus has also been variously depicted with animal heads attached to a piscine body.

In global astronomy

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 ...

, the stars of Cetus are found among two areas: the Black Tortoise of the North (北方玄武, ''Běi Fāng Xuán Wǔ'') and the White Tiger of the West (西方白虎, ''Xī Fāng Bái Hǔ''). The

Tukano The Tucano people (sometimes spelt Tukano) are a group of Indigenous South Americans in the northwestern Amazon, along the Vaupés River and the surrounding area. They are mostly in Colombia, but some are in Brazil. They are us ...

and

Kobeua people The Cubeo are an ethnic group of the Vaupés Department (Colombia). Cubeo is a generic name that is used in local Spanish and appears in the literature in reference to a social and linguistic group. Although the term does not have any meaning in ...

of the Amazon used the stars of Cetus to create a

jaguar The jaguar (''Panthera onca'') is a large cat species and the only living member of the genus '' Panthera'' native to the Americas. With a body length of up to and a weight of up to , it is the largest cat species in the Americas and the th ...

, representing the god of hurricanes and other violent storms. Lambda, Mu, Xi, Nu, Gamma, and Alpha Ceti represented its head; Omicron, Zeta, and Chi Ceti represented its body; Eta Eri, Tau Cet, and Upsilon Cet marked its legs and feet; and Theta, Eta, and Beta Ceti delineated its tail. In

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

, the constellation was called ''Na Kuhi'', and Mira (Omicron Ceti) may have been called ''Kane''.

Namesakes

USS Cetus (AK-77) was a

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

Crater class cargo ship The ''Crater''-class cargo ship were converted EC2-S-C1 type, Liberty ship, Liberty cargo ships, constructed by the United States Maritime Commission (USMC) for use by the United States Navy, US Navy during World War II. The designation 'EC2-S-C1' ...

named after the constellation. "Cetus" is the title of a

ragtime Ragtime, also spelled rag-time or rag time, is a musical style that flourished from the 1890s to 1910s. Its cardinal trait is its syncopated or "ragged" rhythm. Ragtime was popularized during the early 20th century by composers such as Scott ...

piano composition by Tom Brier on the album ''Constellations'' and a 1967 electronic composition by

Olly Wilson Olly Woodrow Wilson, Jr. (September 7, 1937 – March 12, 2018) was an American composer of contemporary classical music, pianist, double bassist, and a musicologist. He was one of the most preeminent composers of African American descent in the ...

Gallery

File:Clash_of_the_Titans.tif, The interacting galaxy pair IC 1623, which lies around 275 million light-years away in the constellation Cetus (The Whale).

References

Bibliography

* * * * Ian Ridpath and Wil Tirion (2007). ''Stars and Planets Guide'', Collins, London. . Princeton University Press, Princeton. *

External links

*
The Deep Photographic Guide to the Constellations: Cetus

Warburg Institute Iconographic Database (over 170 medieval and early modern images of Cetus)
{{DEFAULTSORT:Cetus Constellations Equatorial constellations Constellations listed by Ptolemy Fictional cetaceans Legendary mammals