Crateris
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Crater is a small
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 first constellati ...
in the
southern celestial hemisphere The southern celestial hemisphere, also called the Southern Sky, is the Southern Hemisphere, southern half of the celestial sphere; that is, it lies south of the celestial equator. This arbitrary sphere, on which seemingly fixed stars form cons ...
. Its name is the
latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...
ization of the
Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...
''
krater A krater or crater (, ; , ) was a large two-handled type of vase in Pottery of ancient Greece, Ancient Greek pottery and metalwork, mostly used for the mixing of wine with water. Form and function At a Greek symposium, kraters were placed in ...
'', a type of
cup A cup is an open-top vessel (container) used to hold liquids for drinking, typically with a flattened hemispherical shape, and often with a capacity of about . Cups may be made of pottery (including porcelain), glass, metal, wood, stone, pol ...
used to water down
wine Wine is an alcoholic drink made from Fermentation in winemaking, fermented fruit. Yeast in winemaking, Yeast consumes the sugar in the fruit and converts it to ethanol and carbon dioxide, releasing heat in the process. Wine is most often made f ...
. One of the 48 constellations listed by the second-century astronomer
Ptolemy Claudius Ptolemy (; , ; ; – 160s/170s AD) was a Greco-Roman mathematician, astronomer, astrologer, geographer, and music theorist who wrote about a dozen scientific treatises, three of which were important to later Byzantine science, Byzant ...
, it depicts a cup that has been associated with the god
Apollo Apollo is one of the Twelve Olympians, Olympian deities in Ancient Greek religion, ancient Greek and Ancient Roman religion, Roman religion and Greek mythology, Greek and Roman mythology. Apollo has been recognized as a god of archery, mu ...
and is perched on the back of Hydra the water snake. There is no
star A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...
brighter than third
magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...
in the constellation. Its two brightest stars,
Delta Crateris Delta Crateris (δ Crt, δ Crateris) is a solitary star in the southern constellation of Crater (constellation), Crater. With an apparent visual magnitude of 3.56, it is the brightest star in this rather dim constellation. It has an annual ...
of magnitude 3.56 and Alpha Crateris of magnitude 4.07, are ageing orange
giant star A giant star has a substantially larger radius and luminosity than a main-sequence (or ''dwarf'') star of the same surface temperature. They lie above the main sequence (luminosity class V in the Yerkes spectral classification) on the Hertzsp ...
s that are cooler and larger than the
Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...
.
Beta Crateris Beta Crateris, Latinized from β Crateris, is a binary star system in the southern constellation of Crater. It is visible to the naked eye with an apparent visual magnitude of 4.46. Based upon an annual parallax shift of 9.59  mas a ...
is a
binary star A binary star or binary star system is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved as separate stars us ...
system composed of a white giant star and a
white dwarf A white dwarf is a Compact star, stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very density, dense: in an Earth sized volume, it packs a mass that is comparable to the Sun. No nuclear fusion takes place i ...
. Seven star systems have been found to host
planets A planet is a large, rounded astronomical body that is generally required to be in orbit around a star, stellar remnant, or brown dwarf, and is not one itself. The Solar System has eight planets by the most restrictive definition of the te ...
. A few notable
galaxies A galaxy is a system of stars, stellar remnants, interstellar gas, dust, and 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 Sys ...
, including
Crater 2 Crater 2 is a low-surface-brightness dwarf satellite galaxy of the Milky Way, located approximately 380,000 ly from Earth. Its discovery in 2016 revealed significant gaps in astronomers' understanding of galaxies possessing relatively small ha ...
and
NGC 3981 NGC 3981 is an unbarred spiral galaxy located 65 million light-years away in the constellation of Crater. It was discovered on February 7, 1785, by William Herschel. NGC 3981 is a member of the NGC 4038 Group which is part of the Virgo Superclu ...
, and a famous
quasar A quasar ( ) is an extremely Luminosity, luminous active galactic nucleus (AGN). It is sometimes known as a quasi-stellar object, abbreviated QSO. The emission from an AGN is powered by accretion onto a supermassive black hole with a mass rangi ...
lie within the borders of the constellation.


Mythology

In the
Babylonian star catalogues Babylonian astronomy collated earlier observations and divinations into sets of Babylonian star catalogues, during and after the Kassite rule over Babylonia. These star catalogues, written in cuneiform script, contained lists of constellations, ...
dating from at least 1100 BC, the stars of Crater were possibly incorporated with those of the crow
Corvus ''Corvus'' is a widely distributed genus of passerine birds ranging from medium-sized to large-sized in the family Corvidae. It includes species commonly known as crows, ravens, and rooks. The species commonly encountered in Europe are the car ...
in the Babylonian Raven (MUL.UGA.MUSHEN). British scientist John H. Rogers observed that the adjoining constellation Hydra signified
Ningishzida Ningishzida ( Sumerian: DNIN.G̃IŠ.ZID.DA, possible meaning "Lord f theGood Tree") was a Mesopotamian deity of vegetation, the underworld and sometimes war. He was commonly associated with snakes. Like Dumuzi, he was believed to spend a part ...
, the god of the
underworld The underworld, also known as the netherworld or hell, is the supernatural world of the dead in various religious traditions and myths, located below the world of the living. Chthonic is the technical adjective for things of the underworld. ...
in the Babylonian compendium MUL.APIN. He proposed that Corvus and Crater (along with the water snake Hydra) were death symbols and marked the gate to the underworld. Corvus and Crater also featured in the iconography of
Mithraism Mithraism, also known as the Mithraic mysteries or the Cult of Mithras, was a Roman Empire, Roman mystery religion focused on the god Mithras. Although inspired by Iranian peoples, Iranian worship of the Zoroastrian divinity (''yazata'') Mit ...
, which is thought to have been of middle-eastern origin before spreading into Ancient Greece and Rome. Crater is identified with a story from
Greek mythology Greek mythology is the body of myths originally told by the Ancient Greece, ancient Greeks, and a genre of ancient Greek folklore, today absorbed alongside Roman mythology into the broader designation of classical mythology. These stories conc ...
in which a crow or raven serves
Apollo Apollo is one of the Twelve Olympians, Olympian deities in Ancient Greek religion, ancient Greek and Ancient Roman religion, Roman religion and Greek mythology, Greek and Roman mythology. Apollo has been recognized as a god of archery, mu ...
, and is sent to fetch water, but it delays its journey as it finds some figs and waits for them to ripen before eating them. Finally, it retrieves the water in a cup and takes back a water snake, blaming it for drinking the water. According to the myth, Apollo saw through the fraud, and angrily cast the crow, cup, and snake into the sky. The three constellations were arranged in such a way that the crow was prevented from drinking from the cup, and hence seen as a warning against sinning against the gods.
Phylarchus Phylarchus (, ''Phylarkhos''; fl. 3rd century BC) was a Greek historical writer whose works have been lost, but not before having been considerably used by other historians whose works have survived. Life Phylarchus was a contemporary of Aratus, ...
wrote of a different origin for Crater. He told how the city of Eleusa near
Troy Troy (/; ; ) or Ilion (; ) was an ancient city located in present-day Hisarlik, Turkey. It is best known as the setting for the Greek mythology, Greek myth of the Trojan War. The archaeological site is open to the public as a tourist destina ...
was beset by plague. Its ruler Demiphon consulted an oracle which decreed that a maiden should be sacrificed each year. Demiphon declared that he would choose a maiden by lottery, but he did not include his own daughters. One nobleman, Mastusius, objected, forcing Demiphon to sacrify his daughter. Later, Mastusius killed Demiphon's daughters and tricked the ruler in drinking a cup containing a mixture of their blood and wine. Upon finding out the deed, the king ordered Mastusius and the cup to be thrown into the sea. Crater signifies the cup.


In other cultures

In
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 China, ancient Chinese people have identified stars from 1300 BCE, as Chinese star names later categori ...
, the stars of Crater are located within the constellation of the Vermillion Bird of the South (南方朱雀, ''Nán Fāng Zhū Què''). They depict, along with some stars from Hydra, ''Yi'', the Red Bird's wings. ''Yi'' also denotes the 27th
lunar mansion Often called lunar mansion, a lunar station or lunar house is a segment of the ecliptic through which the Moon passes in orbit of the Moon, its orbit around the Earth. The concept was used by several ancient cultures as part of their calendrical ...
. Alternatively, ''Yi'' depicts a heroic bowman; his bow composed of other stars in Hydra. In the
Society Islands The Society Islands ( , officially ; ) are an archipelago in the South Pacific Ocean that includes the major islands of Tahiti, Mo'orea, Moorea, Raiatea, Bora Bora and Huahine. Politically, they are part of French Polynesia, an overseas country ...
, Crater was recognized as a constellation called ''Moana-'ohu-noa-'ei-ha'a-moe-hara'' ("vortex-ocean-in-which-to-lose-crime").


Characteristics

Covering 282.4 square degrees and hence 0.685% of the sky, Crater ranks 53rd of the 88 constellations in area. It is bordered by
Leo Leo is the Latin word for lion. It most often refers to: * Leo (constellation), a constellation of stars in the night sky * Leo (astrology), an astrological sign of the zodiac * Leo (given name), a given name in several languages, usually mas ...
and
Virgo Virgo may refer to: Arts and entertainment * Virgo (film), a 1970 Egyptian film * Virgo (character), several Marvel Comics characters * Virgo Asmita, a character in the manga ''Saint Seiya: The Lost Canvas'' * ''Virgo'' (album), by Virgo Four, ...
to the north, Corvus to the east, Hydra to the south and west, and
Sextans Sextans is a faint, minor constellation on the celestial equator which was introduced in 1687 by Polish astronomer Johannes Hevelius. Its name is Latin for the astronomical sextant, an instrument that Hevelius made frequent use of in his obs ...
to the northwest. The three-letter abbreviation for the constellation, as adopted by the
International Astronomical Union The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...
in 1922, is "Crt". The official constellation boundaries, as set by Belgian astronomer
Eugène Delporte Eugene is a common male given name that comes from the Greek εὐγενής (''eugenēs''), "noble", literally "well-born", from εὖ (''eu''), "well" and γένος (''genos''), "race, stock, kin".equatorial coordinate system The equatorial coordinate system is a celestial coordinate system widely used to specify the positions of astronomical object, celestial objects. It may be implemented in spherical coordinate system, spherical or Cartesian coordinate system, rect ...
, the
right ascension Right ascension (abbreviated RA; symbol ) is the angular distance of a particular point measured eastward along the celestial equator from the Sun at the equinox (celestial coordinates), March equinox to the (hour circle of the) point in questio ...
coordinates of these borders lie between and , while the
declination In astronomy, declination (abbreviated dec; symbol ''δ'') is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. The declination angle is measured north (positive) or ...
coordinates are between −6.66° and −25.20°. Its position in the
southern celestial hemisphere The southern celestial hemisphere, also called the Southern Sky, is the Southern Hemisphere, southern half of the celestial sphere; that is, it lies south of the celestial equator. This arbitrary sphere, on which seemingly fixed stars form cons ...
means that the whole constellation is visible to observers south of 65°N.


Features


Stars

The German cartographer
Johann Bayer Johann Bayer (; 1572 – 7 March 1625) was a German lawyer and uranographer (celestial cartographer). He was born in Rain in 1572. In 1592, aged 20, he began his study of philosophy and law at the University of Ingolstadt, after which he ...
used the Greek letters
alpha Alpha (uppercase , lowercase ) is the first letter of the Greek alphabet. In the system of Greek numerals, it has a value of one. Alpha is derived from the Phoenician letter ''aleph'' , whose name comes from the West Semitic word for ' ...
through
lambda Lambda (; uppercase , lowercase ; , ''lám(b)da'') is the eleventh letter of the Greek alphabet, representing the voiced alveolar lateral approximant . In the system of Greek numerals, lambda has a value of 30. Lambda is derived from the Phoen ...
to label the most prominent stars in the constellation. Bode added more, though only Psi Crateris remains in use.
John Flamsteed John Flamsteed (19 August 1646 – 31 December 1719) was an English astronomer and the first Astronomer Royal. His main achievements were the preparation of a 3,000-star catalogue, ''Catalogus Britannicus'', and a star atlas called '' Atlas ...
gave 31 stars in Crater and the segment of Hydra immediately below Crater
Flamsteed designation A Flamsteed designation is a combination of a number and constellation name that uniquely identifies most naked eye stars in the 88 modern constellations, modern constellations visible from southern England. They are named after John Flamsteed, au ...
s, naming the resulting constellation Hydra et Crater. Most of these stars lie in Hydra. The three brightest stars—Delta,
Alpha Alpha (uppercase , lowercase ) is the first letter of the Greek alphabet. In the system of Greek numerals, it has a value of one. Alpha is derived from the Phoenician letter ''aleph'' , whose name comes from the West Semitic word for ' ...
, and Gamma Crateris—form a triangle located near the brighter star Nu Hydrae in Hydra. Within the constellation's borders, there are 33 stars brighter than or equal to
apparent magnitude Apparent magnitude () is a measure of the Irradiance, brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction (astronomy), ...
 6.5. Delta Crateris is the brightest star in Crater at magnitude 3.6. Located 163 ± 4
light-year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astr ...
s away, it is an orange
giant star A giant star has a substantially larger radius and luminosity than a main-sequence (or ''dwarf'') star of the same surface temperature. They lie above the main sequence (luminosity class V in the Yerkes spectral classification) on the Hertzsp ...
of
spectral type In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the ...
K0III that is 1.0–1.4 times as massive as the Sun. An ageing star, it has cooled and expanded to times the
Sun's radius Solar radius is a unit of distance used to express the size of objects in astronomy relative to the Sun. The solar radius is usually defined as the radius to the layer in the Sun's photosphere where the optical depth equals 2/3: 1\,R_ = 6.957\ti ...
. It is radiating as much power as the Sun from its outer envelope at an
effective temperature The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature ...
of . Traditionally called Alkes "the cup", and marking the base of the cup is Alpha Crateris, an orange-hued star of magnitude 4.1, that is 141 ± 2 light-years from the Sun. With an estimated mass 1.75 ± 0.24 times that of the Sun, it has exhausted its core hydrogen and expanded to 13.2 ± 0.55 times the Sun's diameter, shining with 69 times its luminosity and an effective temperature of around 4600 K. With a magnitude of 4.5,
Beta Crateris Beta Crateris, Latinized from β Crateris, is a binary star system in the southern constellation of Crater. It is visible to the naked eye with an apparent visual magnitude of 4.46. Based upon an annual parallax shift of 9.59  mas a ...
is a
binary star A binary star or binary star system is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved as separate stars us ...
system, consisting of a white-hued giant star of spectral type A1III and a
white dwarf A white dwarf is a Compact star, stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very density, dense: in an Earth sized volume, it packs a mass that is comparable to the Sun. No nuclear fusion takes place i ...
of spectral type DA1.4, 296 ± 8 light-years from the Sun. Much smaller than the primary, the white dwarf cannot be seen as a separate object, even by the
Hubble Space Telescope The Hubble Space Telescope (HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the Orbiting Solar Observatory, first space telescope, but it is one of the largest and most ...
. Gamma Crateris is a
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 ...
, resolvable in small amateur telescopes. The primary is a
white main sequence star An A-type main-sequence star (A) or A dwarf star is a main-sequence (hydrogen burning) star of spectral type A and luminosity class (five). These stars have spectra defined by strong hydrogen Balmer absorption lines. They measure between 1.7 ...
of spectral type A7V, that is an estimated 1.81 times as massive as the Sun, while the secondary—of magnitude 9.6—has 75% the Sun's mass, and is likely an
orange dwarf A K-type main-sequence star, also referred to as a K-type dwarf, or orange dwarf, is a main-sequence (hydrogen-burning) star of spectral type K and luminosity class V. These stars are intermediate in size between red M-type main-sequence stars ("r ...
. The two stars take at least 1150 years to orbit each other. The system is 85.6 ± 0.8 light-years away from the Sun.
Epsilon Epsilon (, ; uppercase , lowercase or ; ) is the fifth letter of the Greek alphabet, corresponding phonetically to a mid front unrounded vowel or . In the system of Greek numerals it also has the value five. It was derived from the Phoenic ...
and Zeta Crateris mark the Cup's rim. The largest naked eye star in the constellation, Epsilon Crateris is an
evolved Evolution is the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, re ...
K-type giant star with a
stellar classification In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction gratin ...
of K5 III. It has about the same mass as the Sun, but has expanded to 44.7 times the Sun's radius. The star is radiating 391 times the solar luminosity. It is 366 ± 8 light-years distant from the Sun. Zeta Crateris is a binary star system. The primary, component A, is a magnitude 4.95 evolved giant star with a stellar classification of G8 III. It is a
red clump The red clump is a clustering of red giants in the Hertzsprung–Russell diagram at around 5,000 K and absolute magnitude (MV) +0.5, slightly hotter than most red-giant-branch stars of the same luminosity. It is visible as a denser region of ...
star that is generating energy through the fusion of helium at its core. Zeta Crateris has expanded to 13 times the radius of the Sun, and shines with 157 times the luminosity of the Sun.Online data
(
HIP In vertebrate anatomy, the hip, or coxaLatin ''coxa'' was used by Celsus in the sense "hip", but by Pliny the Elder in the sense "hip bone" (Diab, p 77) (: ''coxae'') in medical terminology, refers to either an anatomical region or a joint on t ...
number needed)
The secondary, component B, is a magnitude 7.84 star. Zeta Crateris is a confirmed member of the Sirius supercluster and is a candidate member of the
Ursa Major Moving Group The Ursa Major Moving Group, also known as Collinder 285 and the Ursa Major association, is the closest Stellar kinematics#Moving groups, stellar moving group – a set of stars with common velocities in space and thought to have a common orig ...
, a collection of stars that share a similar motion through space and may have at one time been members of the same
open cluster An open cluster is a type of star cluster made of tens to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way galaxy, and ...
. The system is located 326 ± 9 light-years from the Sun. Variable stars are popular targets for amateur astronomers. Their observations provide valuable contributions to understanding star behaviour. Located near Alkes is the red-hued R Crateris, a
semiregular variable star In astronomy, a semiregular variable star, a type of variable star, is a giant or supergiant of intermediate and late (cooler) spectral type. It shows considerable periodicity in its light changes, accompanied or sometimes interrupted by various i ...
of type SRb and a
spectral classification ''Spectral'' is a 2016 Hungarian-American military science fiction action film co-written and directed by Nic Mathieu. Written with Ian Fried & George Nolfi, the film stars James Badge Dale as DARPA research scientist Mark Clyne, with Max M ...
of M7. It ranges from magnitude 9.8 to 11.2 over an optical period of 160 days. It is 770 ± 40 light-years distant from the Sun. TT Crateris is a
cataclysmic variable In astronomy, cataclysmic variable stars (CVs) are stars which irregularly increase in brightness by a large factor, then drop back down to a quiescent state. They were initially called novae (), since those with an outburst brightness visible to ...
; a binary system composed of a white dwarf around as massive as the Sun in close orbit with an orange dwarf of spectral type K5V. The two orbit each other every 6 hours 26 minutes. The white dwarf strips matter off its companion, forming an
accretion disk An accretion disk is a structure (often a circumstellar disk) formed by diffuse material in orbital motion around a massive central body. The central body is most frequently a star. Friction, uneven irradiance, magnetohydrodynamic effects, and ...
which periodically ignites and erupts. The star system has a magnitude of 15.9 when quiescent, brightening to 12.7 in outburst. SZ Crateris is a magnitude 8.5 BY Draconis type variable star. It is a nearby star system located about 42.9 ± 1.0 light-years from the Sun, and is a member of the Ursa Major Moving Group.
HD 98800 HD 98800, also catalogued as TV Crateris (TV Crt), is a quadruple star system in the constellation of Crater (constellation), Crater (the cup). Stellar parallax, Parallax measurements made by the Hipparcos spacecraft put it at a distan ...
, also known as TV Crateris, is a quadruple star system around 7–10 million years old, made up of two pairs of stars in close orbit. One pair has a
debris disk A debris disk (American English), or debris disc ( Commonwealth English), is a circumstellar disk of dust and debris in orbit around a star. Sometimes these disks contain prominent rings, as seen in the image of Fomalhaut on the right. Debris ...
that contains dust and gas orbiting them both. Spanning the distance between 3 and 5
astronomical units The astronomical unit (symbol: au or AU) is a unit of length defined to be exactly equal to . Historically, the astronomical unit was conceived as the average Earth-Sun distance (the average of Earth's aphelion and perihelion), before its mode ...
from the stars, it is thought to be a
protoplanetary disk A protoplanetary disk is a rotating circumstellar disc of dense gas and dust surrounding a young newly formed star, a T Tauri star, or Herbig Ae/Be star. The protoplanetary disk may not be considered an accretion disk; while the two are sim ...
. DENIS-P J1058.7-1548 is a
brown dwarf Brown dwarfs are substellar objects that have more mass than the biggest gas giant planets, but less than the least massive main sequence, main-sequence stars. Their mass is approximately 13 to 80 Jupiter mass, times that of Jupiter ()not big en ...
less than 5.5% as massive as the Sun. With a surface temperature of between 1700 and 2000 K, it is cool enough for clouds to form. Variations in its brightness in visible and infrared spectra suggest it has some form of atmospheric cloud cover.
HD 96167 HD 96167 is a double star system with an exoplanetary companion in the southern constellation of Crater. The apparent visual magnitude of this system is 8.09, which is too faint to be readily visible to the naked eye. It is located at a d ...
is a star 1.31 ± 0.09 times as massive as the Sun, that has most likely exhausted its core hydrogen and begun expanding and cooling into a yellow subgiant with a diameter 1.86 ± 0.07 times that of the Sun, and 3.4 ± 0.2 times its luminosity. Analysis of its radial velocity revealed it has a planet with a minimum mass 68% that of Jupiter, which takes 498.9 ± 1.0 days to complete an orbit. With the orbital separation varying between 0.38 and 2.22 astronomical units, the orbit is highly
eccentric 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 ...
. The stellar system is 279 ± 1 light-years away from the Sun. HD 98649 is a yellow main sequence star, classified as a G4V, that has the same mass and diameter as the Sun, but has only 86% of its luminosity. In 2012, a long-period ( 4951 days) planet companion, at least 6.8 times as massive as Jupiter, was discovered by
radial velocity method Doppler spectroscopy (also known as the radial-velocity method, or colloquially, the wobble method) is an indirect method for finding extrasolar planets and brown dwarfs from radial-velocity measurements via observation of Doppler shifts in th ...
. Its orbit was calculated to be highly eccentric, swinging out to 10.6 astronomical units away from its star, and hence a candidate for direct imaging. BD-10°3166 is a metallic orange main sequence star of spectral type K3.0V, 268 ± 10 light-years distant from the Sun. It was found to have a
hot Jupiter Hot Jupiters (sometimes called hot Saturns) are a class of gas giant exoplanets that are inferred to be physically similar to Jupiter (i.e. Jupiter analogue, Jupiter analogues) but that have very short orbital periods (). The close proximity to t ...
-type planet that has a
minimum mass In astronomy, minimum mass is the lower-bound calculated mass of observed objects such as planets, stars, binary systems, nebulae, and black holes. Minimum mass is a widely cited statistic for extrasolar planets detected by the radial velocit ...
of 48% of
Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a Jupiter mass, mass more than 2.5 times that of all the other planets in the Solar System combined a ...
's, and takes only 3.49 days to complete an orbit. WASP-34 is a sun-like star of spectral type G5V that has 1.01 ± 0.07 times the mass and 0.93 ± 0.12 times the diameter of the Sun. It has a planet 0.59 ± 0.01 times as massive as Jupiter that takes 4.317 days to complete an orbit. The system is 432 ± 3 light-years distant from the Sun.


Deep-sky objects

The Crater 2 dwarf is a satellite galaxy of the Milky Way, located approximately 380,000 light-years from the Sun. NGC 3511 is a
spiral galaxy Spiral galaxies form a galaxy morphological classification, class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''
seen nearly edge-on, of magnitude 11.0, located 2° west of Beta Crateris. Located 11' away is NGC 3513, a
barred spiral galaxy A barred spiral galaxy is a spiral galaxy with a central bar-shaped structure composed of stars. Bars are found in about two thirds of all spiral galaxies in the local universe, and generally affect both the motions of stars and interstellar gas ...
.
NGC 3981 NGC 3981 is an unbarred spiral galaxy located 65 million light-years away in the constellation of Crater. It was discovered on February 7, 1785, by William Herschel. NGC 3981 is a member of the NGC 4038 Group which is part of the Virgo Superclu ...
is a spiral galaxy with two wide and perturbed spiral arms. It is a member of the NGC 4038 Group, which, along with NGC 3672 and NGC 3887, are part of a group of 45 galaxies known as the Crater Cloud within the
Virgo Supercluster The Local Supercluster (LSC or LS), or Virgo Supercluster is a formerly defined supercluster containing the Virgo Cluster and Local Group, which itself contains the Milky Way and Andromeda galaxies, as well as others. At least 100 galaxy group ...
. RX J1131 is a
quasar A quasar ( ) is an extremely Luminosity, luminous active galactic nucleus (AGN). It is sometimes known as a quasi-stellar object, abbreviated QSO. The emission from an AGN is powered by accretion onto a supermassive black hole with a mass rangi ...
located 6 billion light-years away from the Sun. The black hole in the center of the quasar was the first black hole whose spin has ever been directly measured. GRB 011211 was a
gamma-ray burst In gamma-ray astronomy, gamma-ray bursts (GRBs) are extremely energetic events occurring in distant Galaxy, galaxies which represent the brightest and most powerful class of explosion in the universe. These extreme Electromagnetic radiation, ele ...
(GRB) detected on December 11, 2001. The burst lasted 270 seconds, making it the longest burst that had ever been detected by
X-ray astronomy X-ray astronomy is an observational branch of astronomy which deals with the study of X-ray observation and detection from astronomical objects. X-radiation is absorbed by the Earth's atmosphere, so instruments to detect X-rays must be taken to ...
satellite
BeppoSAX BeppoSAX was an Italian–Dutch satellite for X-ray astronomy which played a crucial role in resolving the origin of gamma-ray bursts (GRBs), the most energetic events known in the universe. It was the first X-ray mission capable of simultaneousl ...
up to that point. GRB 030323 lasted 26 seconds and was detected on 23 March 2003.


Meteor showers

The Eta Craterids are a faint meteor shower that takes place between 11 and 22 January, peaking around January 16 and 17, near Eta Crateris.


See also

* Crater (Chinese astronomy)


Notes


References


External links


The Deep Photographic Guide to the Constellations: Crater



Warburg Institute Iconographic Database (medieval and early modern images of Crater)
{{DEFAULTSORT:Crater (Constellation) Constellations Southern constellations Constellations listed by Ptolemy