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Tucana (The Toucan) 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 ...
of stars in the
southern sky The southern celestial hemisphere, also called the Southern Sky, is the southern half of the celestial sphere; that is, it lies south of the celestial equator. This arbitrary sphere, on which seemingly fixed stars form constellations, appears ...
, named after the toucan, a
South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
n
bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...
. It is one of twelve constellations conceived in the late sixteenth century by
Petrus Plancius Petrus Plancius (; 1552 – 15 May 1622) was a Dutch-Flemish astronomer, cartographer and clergyman. He was born as Pieter Platevoet in Dranouter, now in Heuvelland, West Flanders. He studied theology in Germany and England. At the age of 24 he ...
from the observations of
Pieter Dirkszoon Keyser Pieter Dirkszoon Keyser (occasionally Petrus Theodorus;  – 11 September 1596) was a Dutch navigator and celestial cartographer who mapped several constellations on the southern celestial hemisphere. Voyages and star observation Little is ...
and
Frederick de Houtman Frederick de Houtman ( – 21 October 1627) was a Dutch explorer, navigator, and colonial governor who sailed on the first Dutch expedition to the East Indies from 1595 until 1597, during which time he made observations of the southern cel ...
. Tucana first appeared on a
celestial globe Celestial globes show the apparent positions of the stars in the sky. They omit the Sun, Moon, and planets because the positions of these bodies vary relative to those of the stars, but the ecliptic, along which the Sun moves, is indicated. The ...
published in 1598 in Amsterdam by Plancius and
Jodocus Hondius Jodocus Hondius (Latinized version of his Dutch language, Dutch name: ''Joost de Hondt'') (17 October 1563 – 12 February 1612) was a Flemish people, Flemish and Dutch engraving, engraver and cartographer. He is sometimes called Jodocus Hon ...
and was depicted in
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 ...
's star atlas '' Uranometria'' of 1603. French explorer and astronomer
Nicolas Louis de Lacaille Abbé Nicolas-Louis de Lacaille (; 15 March 171321 March 1762), formerly sometimes spelled de la Caille, was a French astronomer and geodesist who named 14 out of the 88 constellations. From 1750 to 1754, he studied the sky at the Cape of Good ...
gave its stars
Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek or Latin letter followed by the genitive form of its parent constellation's Latin name. The original list of Bayer designations contained 1,564 stars. ...
s in 1756. The constellations Tucana, Grus, Phoenix and Pavo are collectively known as the "Southern Birds". Tucana is not a prominent constellation as all of its stars are third magnitude or fainter; the brightest is Alpha Tucanae with an apparent visual magnitude of 2.87. Beta Tucanae is a star system with six member stars, while
Kappa Kappa (uppercase Κ, lowercase κ or cursive ; el, κάππα, ''káppa'') is the 10th letter of the Greek alphabet, representing the voiceless velar plosive sound in Ancient and Modern Greek. In the system of Greek numerals, has a value o ...
is a quadruple system. Five star systems have been found to have
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 ...
s to date. The constellation contains
47 Tucanae 47 Tucanae, or 47 Tuc (also designated NGC 104) is a globular cluster located in the constellation Tucana. It is about away from Earth, and 120 light years in diameter. 47 Tuc can be seen with the naked eye, with an apparent magnitude of 4.1. It ...
, one of the brightest globular clusters in the sky, and most of the
Small Magellanic Cloud The Small Magellanic Cloud (SMC), or Nubecula Minor, is a dwarf galaxy near the Milky Way. Classified as a dwarf irregular galaxy, the SMC has a D25 isophotal diameter of about , and contains several hundred million stars. It has a total mass of ...
.


History

Tucana is one of the twelve constellations established by the Dutch astronomer
Petrus Plancius Petrus Plancius (; 1552 – 15 May 1622) was a Dutch-Flemish astronomer, cartographer and clergyman. He was born as Pieter Platevoet in Dranouter, now in Heuvelland, West Flanders. He studied theology in Germany and England. At the age of 24 he ...
from the observations of the southern sky by the Dutch explorers
Pieter Dirkszoon Keyser Pieter Dirkszoon Keyser (occasionally Petrus Theodorus;  – 11 September 1596) was a Dutch navigator and celestial cartographer who mapped several constellations on the southern celestial hemisphere. Voyages and star observation Little is ...
and
Frederick de Houtman Frederick de Houtman ( – 21 October 1627) was a Dutch explorer, navigator, and colonial governor who sailed on the first Dutch expedition to the East Indies from 1595 until 1597, during which time he made observations of the southern cel ...
, who had sailed on the first Dutch trading expedition, known as the ''
Eerste Schipvaart The First Dutch Expedition to East Indies (Dutch: ''Eerste Schipvaart'') was an expedition that took place from 1595 to 1597. It was instrumental in opening up the Indonesian spice trade to the merchants that eventually formed the Dutch E ...
'', to the
East Indies The East Indies (or simply the Indies), is a term used in historical narratives of the Age of Discovery. The Indies refers to various lands in the East or the Eastern hemisphere, particularly the islands and mainlands found in and around t ...
. It first appeared on a celestial globe published in 1598 in Amsterdam by Plancius with
Jodocus Hondius Jodocus Hondius (Latinized version of his Dutch language, Dutch name: ''Joost de Hondt'') (17 October 1563 – 12 February 1612) was a Flemish people, Flemish and Dutch engraving, engraver and cartographer. He is sometimes called Jodocus Hon ...
. The first depiction of this constellation in a
celestial atlas Celestial cartography, uranography, astrography or star cartography is the aspect of astronomy and branch of cartography concerned with mapping stars, galaxies, and other astronomical objects on the celestial sphere. Measuring the position ...
was in the German cartographer
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 ...
's '' Uranometria'' of 1603. Both Plancius and Bayer depict it as a toucan. De Houtman included it in his southern star catalogue the same year under the Dutch name ''Den Indiaenschen Exster, op Indies Lang ghenaemt'' "the Indian magpie, named Lang in the Indies", by this meaning a particular bird with a long beak—a
hornbill Hornbills (Bucerotidae) are a family (biology), family of bird found in tropical and subtropical Africa, Asia and Melanesia. They are characterized by a long, down-curved bill which is frequently brightly coloured and sometimes has a Casque (an ...
, a bird native to the
East Indies The East Indies (or simply the Indies), is a term used in historical narratives of the Age of Discovery. The Indies refers to various lands in the East or the Eastern hemisphere, particularly the islands and mainlands found in and around t ...
. A 1603 celestial globe by Willem Blaeu depicts it with a casque. It was interpreted on Chinese charts as '' Niǎohuì'' "bird's beak", and in England as "Brasilian Pye", while
Johannes Kepler Johannes Kepler (; ; 27 December 1571 – 15 November 1630) was a German astronomer, mathematician, astrologer, natural philosopher and writer on music. He is a key figure in the 17th-century Scientific Revolution, best known for his laws ...
and Giovanni Battista Riccioli termed it ''Anser Americanus'' "American Goose", and Caesius as ''Pica Indica''. Tucana and the nearby constellations Phoenix, Grus and Pavo are collectively called the "Southern Birds".


Characteristics

Irregular in shape, Tucana is bordered by Hydrus to the east, Grus and Phoenix to the north,
Indus The Indus ( ) is a transboundary river of Asia and a trans-Himalayan river of South and Central Asia. The river rises in mountain springs northeast of Mount Kailash in Western Tibet, flows northwest through the disputed region of Kashmir, ...
to the west and Octans to the south. Covering 295 square degrees, it ranks 48th of the 88 constellations in size. The recommended three-letter abbreviation for the constellation, as adopted by the
International Astronomical Union The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...
in 1922, is "Tuc". The official constellation boundaries, as set by Belgian astronomer Eugène Delporte in 1930, are defined by a polygon of 10 segments. In the equatorial coordinate system, 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 March equinox to the (hour circle of the) point in question above the earth. When paired w ...
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. Declination's angle is measured north or south of the ...
coordinates are between −56.31° and −75.35°. As one of the deep southern constellations, it remains below the horizon at latitudes north of the 30th parallel in the
Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...
, and is
circumpolar Circumpolar may refer to: * Antarctic region ** Antarctic Circle ** the Antarctic Circumpolar Current ** Subantarctic ** List of Antarctic and subantarctic islands ** Antarctic Convergence ** Antarctic Circumpolar Wave ** Antarctic Ocean * Arctic ...
at latitudes south of the 50th parallel in the Southern Hemisphere.


Features


Stars

Although he depicted Tucana on his chart, Bayer did not assign its stars
Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek or Latin letter followed by the genitive form of its parent constellation's Latin name. The original list of Bayer designations contained 1,564 stars. ...
s. French explorer and astronomer
Nicolas Louis de Lacaille Abbé Nicolas-Louis de Lacaille (; 15 March 171321 March 1762), formerly sometimes spelled de la Caille, was a French astronomer and geodesist who named 14 out of the 88 constellations. From 1750 to 1754, he studied the sky at the Cape of Good ...
labelled them Alpha to Rho in 1756, but omitted Omicron and Xi, and labelled a pair of stars close together Lambda Tucanae, and a group of three stars Beta Tucanae. In 1879, American astronomer
Benjamin Gould Benjamin Apthorp Gould (September 27, 1824 – November 26, 1896) was a pioneering American astronomer. He is noted for creating the ''Astronomical Journal'', discovering the Gould Belt, and for founding of the Argentine National Observatory an ...
designated a star Xi Tucanae—this had not been given a designation by Lacaille who had recognized it as nebulous, and it is now known as the globular cluster 47 Tucanae. Mu Tucanae was dropped by
Francis Baily Francis Baily (28 April 177430 August 1844) was an English astronomer. He is most famous for his observations of "Baily's beads" during a total eclipse of the Sun. Baily was also a major figure in the early history of the Royal Astronomical S ...
, who felt the star was too faint to warrant a designation, and Kappa's two components came to be known as Kappa1 and Kappa2. The layout of the brighter stars of Tucana has been likened to a kite. Within the constellation's boundaries are around 80 stars brighter than an apparent magnitude of 7. At an apparent magnitude of 2.86, Alpha Tucanae is the brightest star in the constellation and marks the toucan's head. It is an orange subgiant of spectral type K3III around 199
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 distant from the
Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar S ...
. A cool star with a surface temperature of 4300 K, it is 424 times as luminous as the sun and 37 times its diameter. It is 2.5 to 3 times as massive. Alpha Tucanae is a
spectroscopic binary A binary star is a system of two star, stars that are gravity, 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 using a telescope as separa ...
, which means that the two stars have not been individually resolved using a telescope, but the presence of the companion has been inferred from measuring changes in the
spectrum A spectrum (plural ''spectra'' or ''spectrums'') is a condition that is not limited to a specific set of values but can vary, without gaps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors i ...
of the primary. The orbital period of the binary system is 4197.7 days (11.5 years). Nothing is known about the companion. Two degrees southeast of Alpha is the red-hued
Nu Tucanae ν Tucanae, Latinized as Nu Tucanae, is a solitary, variable star in the southern constellation of Tucana. This red-hued object is visible to the naked eye as a faint star with an apparent visual magnitude that fluctuates around +4.80. ...
, of spectral type M4III and lying around 290 light-years distant. It is classified as 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 showing considerable periodicity in its light changes, accompanied or sometimes interrupted by various irre ...
and its brightness varies from magnitude +4.75 to +4.93. Described by Richard Hinckley Allen as bluish,
Gamma Tucanae Gamma Tucanae, Latinized from γ Tucanae, is a star in the constellation Tucana, marking the toucan's beak. It is faintly visible to the naked eye with an apparent visual magnitude of +3.99. Based upon an annual parallax shift of 43.3 ...
is a yellow-white sequence star of spectral type F4V and an apparent magnitude of 4.00 located around 75 light-years from Earth. It also marks the toucan's beak.
Beta Beta (, ; uppercase , lowercase , or cursive ; grc, βῆτα, bē̂ta or ell, βήτα, víta) is the second letter of the Greek alphabet. In the system of Greek numerals, it has a value of 2. In Modern Greek, it represents the voiced labiod ...
,
Delta Delta commonly refers to: * Delta (letter) (Δ or δ), a letter of the Greek alphabet * River delta, at a river mouth * D (NATO phonetic alphabet: "Delta") * Delta Air Lines, US * Delta variant of SARS-CoV-2 that causes COVID-19 Delta may also re ...
and
Kappa Kappa (uppercase Κ, lowercase κ or cursive ; el, κάππα, ''káppa'') is the 10th letter of the Greek alphabet, representing the voiceless velar plosive sound in Ancient and Modern Greek. In the system of Greek numerals, has a value o ...
are multiple
star system A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction. A large group of stars bound by gravitation is generally called a '' star cluster'' or '' galaxy'', although, broadly speak ...
s containing six, two and four stars respectively. Located near the tail of the toucan, Beta Tucanae's two brightest components, Beta1 and Beta2 are separated by an angle of 27
arcsecond A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of one degree. Since one degree is of a turn (or complete rotation), one minute of arc is of a turn. The na ...
s and have apparent magnitudes of 4.4 and 4.5 respectively. They can be separated in small telescopes. A third star, Beta3 Tucanae, is separated by 10 arcminutes from the two, and able to be seen as a separate star with the unaided eye. Each star is itself a binary star, making six in total. Lying in the southwestern corner of the constellation around 251 light-years away from Earth, Delta Tucanae consists of a blue-white primary contrasting with a yellowish companion. Delta Tucanae A is a
main sequence 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 Her ...
star of spectral type B9.5V and an apparent magnitude of 4.49. The companion has an apparent magnitude of 9.3. The Kappa Tucanae system shines with a combined apparent magnitude of 4.25, and is located around 68 light-years from the Solar System. The brighter component is a yellowish star, known as Kappa Tucanae A with an apparent magnitude of 5.33 and spectral type F6V, while the fainter lies 5 arcseconds to the northwest. Known as Kappa Tucanae B, it has an apparent magnitude of 7.58 and spectral type K1V. Five arcminutes to the northwest is a fainter star of apparent magnitude 7.24 —actually a pair of orange main sequence stars of spectral types K2V and K3V, which can be seen individually as stars one arcsecond apart with a telescope such as a
Dobsonian A Dobsonian telescope is an altazimuth-mounted Newtonian telescope design popularized by John Dobson in 1965 and credited with vastly increasing the size of telescopes available to amateur astronomers. Dobson's telescopes featured a simplified ...
with high power. Lambda Tucanae is an optical double—that is, the name is given to two stars (Lambda1 and Lambda2) which appear close together from our viewpoint, but are in fact far apart in space. Lambda1 is itself a binary star, with two components—a yellow-white star of spectral type F7IV-V and an apparent magnitude of 6.22, and a yellow main sequence star of spectral type G1V and an apparent magnitude of 7.28. The system is 186 light-years distant. Lambda2 is an orange subgiant of spectral type K2III that is expanding and cooling and has left the main sequence. Of apparent magnitude 5.46, it is approximately 220 light-years distant from
Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
.
Epsilon Tucanae Epsilon Tucanae (ε Tuc, ε Tucanae) is a solitary star in the southern constellation of Tucana. With an apparent visual magnitude of +4.50, it is faintly visible to the naked eye. Based upon an annual parallax shift of 8.74 mas as ...
traditionally marks the toucan's left leg. A B-type subgiant, it has a spectral type B9IV and an apparent magnitude of 4.49. It is approximately 373 light-years from
Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
. It is around four times as massive as our Sun. Theta Tucanae is a white A-type star around 423 light-years distant from Earth, which is actually a close binary system. The main star is classified as a Delta Scuti variable—a class of short period (six hours at most) pulsating stars that have been used as
standard candles The cosmic distance ladder (also known as the extragalactic distance scale) is the succession of methods by which astronomers determine the distances to celestial objects. A ''direct'' distance measurement of an astronomical object is possible o ...
and as subjects to study
asteroseismology Asteroseismology or astroseismology is the study of oscillations in stars. Stars have many resonant modes and frequencies, and the path of sound waves passing through a star depends on the speed of sound, which in turn depends on local temperature ...
. It is around double the Sun's mass, having siphoned off one whole
solar mass The solar mass () is a standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass ...
from its companion, now a hydrogen-depleted dwarf star of around only 0.2 solar masses. The system shines with a combined light that varies between magnitudes 6.06 to 6.15 every 70 to 80 minutes. Zeta Tucanae is a yellow-white main sequence star of spectral type F9.5V and an apparent magnitude of 4.20 located 28 light-years away from the Solar System. Despite having a slightly lower mass, this star is more luminous than the Sun. The composition and mass of this star are very similar to the Sun, with a slightly lower mass and an estimated age of three billion years. The solar-like qualities make it a target of interest for investigating the possible existence of a life-bearing planet. It appears to have a debris disk orbiting it at a minimum radius of 2.3
astronomical unit The astronomical unit (symbol: au, or or AU) is a unit of length, roughly the distance from Earth to the Sun and approximately equal to or 8.3 light-minutes. The actual distance from Earth to the Sun varies by about 3% as Earth orbits t ...
s. As of 2009, no planet has been discovered in orbit around this star. Five star systems have been found to have planets, four of which have been discovered by the
High Accuracy Radial Velocity Planet Searcher The High Accuracy Radial Velocity Planet Searcher (HARPS) is a high-precision echelle planet-finding spectrograph installed in 2002 on the ESO's 3.6m telescope at La Silla Observatory in Chile. The first light was achieved in February 2003. H ...
(HARPS) in Chile.
HD 4308 HD 4308 is a single star in the southern constellation of Tucana. It has a yellow hue and is a challenge to view with the naked eye even under good seeing conditions, having an apparent visual magnitude of 6.54. This object is located at ...
is a star with around 83% of the Sun's mass located 72 light-years away with a super-Earth planet with an orbital period of around 15 days.
HD 215497 HD 215497 is a single star in the southern constellation of Tucana. It has an orange hue with an apparent visual magnitude of 8.96, which is too dim to be viewed with the naked eye. A 2015 survey ruled out the existence of any stellar comp ...
is an orange star of spectral type K3V around 142 light-years distant. It is orbited by a hot super-Earth every 3 days and a second planet around the size of Saturn with a period of around 567 days. HD 221287 has a spectral type of F7V and lies 173 light-years away, and has a super-Jovian planet.
web preprint
HD 7199 has spectral type KOIV/V and is located 117 light-years away. It has a planet with around 30% the mass of Jupiter that has an orbital period of 615 days.
HD 219077 HD 219077 is a faint, yellow-hued star in the southern constellation of Tucana. It has an apparent visual magnitude of +6.12, which is near the lower limit on stars visible to the naked eye. Based upon an annual parallax shift of 34.25&nb ...
has a planet around 10 times as massive as Jupiter in a highly eccentric orbit.


Deep-sky objects

The second-brightest globular cluster in the sky after Omega Centauri,
47 Tucanae 47 Tucanae, or 47 Tuc (also designated NGC 104) is a globular cluster located in the constellation Tucana. It is about away from Earth, and 120 light years in diameter. 47 Tuc can be seen with the naked eye, with an apparent magnitude of 4.1. It ...
(NGC 104) lies just west of the
Small Magellanic Cloud The Small Magellanic Cloud (SMC), or Nubecula Minor, is a dwarf galaxy near the Milky Way. Classified as a dwarf irregular galaxy, the SMC has a D25 isophotal diameter of about , and contains several hundred million stars. It has a total mass of ...
. Only 14,700 light-years distant from Earth, it is thought to be around 12 billion years old. Mostly composed of old, yellow stars, it does possess a contingent of
blue stragglers A blue straggler is a main-sequence star in an open or globular cluster that is more luminous and bluer than stars at the main sequence turnoff point for the cluster. Blue stragglers were first discovered by Allan Sandage in 1953 while performin ...
, hot stars that are hypothesized to form from
binary star merger Binary may refer to: Science and technology Mathematics * Binary number, a representation of numbers using only two digits (0 and 1) * Binary function, a function that takes two arguments * Binary operation, a mathematical operation that ...
s. 47 Tucanae has an apparent magnitude of 3.9, meaning that it is visible to the naked eye; it is a Shapley class III cluster, which means that it has a clearly defined nucleus. Near to 47 Tucana on the sky, and often seen in wide-field photographs showing it, are two much more distant globular clusters associated with the SMC: NGC 121, 10 arcminutes away from the bigger cluster's edge, and
Lindsay 8 Lindsay may refer to: People *Clan Lindsay, a Scottish family clan *Lindsay (name), an English surname and given name, derived from the Scottish clan name; variants include Lindsey, Lyndsay, Linsay, Linsey, Lyndsey, Lyndsy, Lynsay, Lynsey Places ...
.
NGC 362 NGC 362 (also known as Caldwell 104) is a globular cluster located in the constellation Tucana in the Southern Hemisphere, slightly north of the Small Magellanic Cloud, to which it is completely unrelated. It was discovered on August 1, 1826 ...
is another globular cluster in Tucana with an apparent magnitude of 6.4, 27,700 light-years from Earth. Like neighboring 47 Tucanae, NGC 362 is a Shapley class III cluster and among the brightest globular clusters in the sky. Unusually for a globular cluster, its orbit takes it very close to the center of the Milky Way—approximately 3,000 light-years. It was discovered in the 1820s by James Dunlop. Its stars become visible at 180x magnification through a telescope. Located at the southern end of Tucana, the Small Magellanic Cloud is a dwarf galaxy that is one of the nearest neighbors to 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 ...
galaxy at a distance of 210,000 light-years. Though it probably formed as a disk shape, tidal forces from the Milky Way have distorted it. Along with the
Large Magellanic Cloud The Large Magellanic Cloud (LMC), or Nubecula Major, is a satellite galaxy of the Milky Way. At a distance of around 50 kiloparsecs (≈160,000  light-years), the LMC is the second- or third-closest galaxy to the Milky Way, after the ...
, it lies within the Magellanic Stream, a cloud of gas that connects the two galaxies.
NGC 346 NGC 346 is a young open cluster of stars with associated nebula located in the Small Magellanic Cloud (SMC) that appears in the southern constellation of Tucana. It was discovered August 1, 1826 by Scottish astronomer James Dunlop. J. L. E. Drey ...
is a star-forming region located in the Small Magellanic Cloud. It has an apparent magnitude of 10.3. Within it lies the triple star system
HD 5980 HD 5980 is a multiple star system on the outskirts of NGC 346 in the Small Magellanic Cloud (SMC) and is one of the brightest stars in the SMC. HD 5980 has at least three components among the most luminous stars known: the unusual ...
, each of its members among the most luminous stars known. The
Tucana Dwarf The Tucana Dwarf Galaxy is a dwarf galaxy in the constellation Tucana. It was discovered in 1990 by R.J. Lavery of Mount Stromlo Observatory. It is composed of very old stars and is very isolated from other galaxies. Its location on the opposite ...
galaxy, which was discovered in 1990, is a dwarf spheroidal galaxy of type dE5 that is an isolated member of the
Local Group The Local Group is the galaxy group that includes the Milky Way. It has a total diameter of roughly , and a total mass of the order of . It consists of two collections of galaxies in a "dumbbell" shape: the Milky Way and its satellites form ...
. It is located from the Solar System and around from the barycentre of the Local Group—the second most remote of all member galaxies after the
Sagittarius Dwarf Irregular Galaxy The Sagittarius Dwarf Irregular Galaxy (SagDIG) is a dwarf galaxy in the constellation of Sagittarius. (SagDIG should not be confused with the Sagittarius Dwarf Spheroidal Galaxy, SagDEG, a satellite galaxy of the Milky Way discovered decades ...
. The barred spiral galaxy
NGC 7408 NGC commonly refers to: * New General Catalogue of Nebulae and Clusters of Stars, a catalogue of deep sky objects in astronomy NGC may also refer to: Companies * NGC Corporation, name of US electric company Dynegy, Inc. from 1995 to 1998 * Nati ...
is located 3 degrees northwest of Delta Tucanae, and was initially mistaken for a planetary nebula. In 1998, part of the constellation was the subject of a two-week observation program by the
Hubble Space Telescope The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most versa ...
, which resulted in the Hubble Deep Field South. The potential area to be covered needed to be at the poles of the telescope's orbit for continuous observing, with the final choice resting upon the discovery of a
quasar A quasar is an extremely Luminosity, luminous active galactic nucleus (AGN). It is pronounced , and sometimes known as a quasi-stellar object, abbreviated QSO. This emission from a galaxy nucleus is powered by a supermassive black hole with a m ...
, QSO J2233-606, in the field.


See also

*
Tucana (Chinese astronomy) The modern constellation Tucana is not included in the Three Enclosures and Twenty-Eight Mansions system of traditional Chinese uranography because its stars are too far south for observers in China to know about them prior to the introduction of ...


Notes


References


Cited texts

*


External links


The Deep Photographic Guide to the Constellations: Tucana
{{DEFAULTSORT:Tucana Southern constellations Legendary birds Constellations listed by Petrus Plancius Dutch celestial cartography in the Age of Discovery Astronomy in the Dutch Republic 1590s in the Dutch Republic