Indus 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 ...

in the southern sky first professionally surveyed by Europeans in the 1590s and mapped on a globe 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 ...

by early 1598. It was included on a plate illustrating southern constellations in

Bayer Bayer AG (, commonly pronounced ; ) is a German multinational corporation, multinational pharmaceutical and biotechnology company and one of the largest pharmaceutical companies in the world. Headquartered in Leverkusen, Bayer's areas of busi ...

's sky atlas ''

Uranometria ''Uranometria'' is a star atlas produced by Johann Bayer. It was published in Augsburg in 1603 by Christoph Mangle (''Christophorus Mangus'') under the full title ''Uranometria: omnium asterismorum continens schemata, nova methodo delineata, ae ...

'' in 1603. It lies well south of the

Tropic of Capricorn The Tropic of Capricorn (or the Southern Tropic) is the circle of latitude that contains the subsolar point at the December (or southern) solstice. It is thus the southernmost latitude where the Sun can be seen directly overhead. It also reac ...

but its triangular shape can be seen for most of the year from the

Equator The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can als ...

. It is elongated from north to south and has a complex boundary. The English translation of its name is generally given as ''the Indian'', though it is unclear which indigenous people the constellation was originally supposed to represent.

Features

Indus lacks stars of the top 100 in brightness viewed from the solar system (apparent magnitude). Two of its stars rank of third magnitude and three of fourth magnitude.

Alpha Indi Alpha (uppercase , lowercase ; grc, ἄλφα, ''álpha'', or ell, άλφα, álfa) 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 , whic ...

, its brightest, is an

orange 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 Press ...

of magnitude 3.1, 101 light-years away.

Beta Indi Beta Indi, Latinized from β Indi, is the second brightest star in the southern constellation of Indus. It is visible to the naked eye as a faint, orange-hued point of light with an apparent visual magnitude of 3.67. The star ...

is an orange giant of magnitude 3.7, 600 light-years distant.

Delta Indi Delta Indi, Latinized from δ Indi, is a binary star system in the southern constellation of Indus. It is visible to the naked eye with a combined apparent visual magnitude of +4.40. The brighter primary, designated component A, is ma ...

is a white star of magnitude 4.4, 185 light-years from Earth. The three form a near-perfect

right-angled triangle A right triangle (American English) or right-angled triangle (British), or more formally an orthogonal triangle, formerly called a rectangled triangle ( grc, ὀρθόσγωνία, lit=upright angle), is a triangle in which one angle is a right an ...

, such that Beta marks the right angle and is in the south-east.

Epsilon Indi Epsilon Indi, Latinized from ε Indi, is a star system located at a distance of approximately 12 light-years from Earth in the southern constellation of Indus. The star has an orange hue and is faintly visible to the naked eye with an a ...

is one of the closest stars to

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 ...

, approximately 11.8

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 away. It is an

orange dwarf A K-type main-sequence star, also referred to as a K-type dwarf or an 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 ...

of magnitude 4.7, meaning that the yellow dwarf

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 ...

is slightly hotter and larger. The system has been discovered to contain a pair of binary

brown dwarfs Brown dwarfs (also called failed stars) are substellar objects that are not massive enough to sustain nuclear fusion of ordinary hydrogen ( 1H) into helium in their cores, unlike a main-sequence star. Instead, they have a mass between the most m ...

, and has long been a prime candidate in

SETI The search for extraterrestrial intelligence (SETI) is a collective term for scientific searches for intelligent extraterrestrial life, for example, monitoring electromagnetic radiation for signs of transmissions from civilizations on other p ...

studies. This star has the third-highest

proper motion Proper motion is the astrometric measure of the observed changes in the apparent places of stars or other celestial objects in the sky, as seen from the center of mass of the Solar System, compared to the abstract background of the more dista ...

of all visible to the unaided eye, as ranks behind

Groombridge 1830 Groombridge 1830 (also known as 1830 Groombridge or Argelander's Star)Peters, C. A. F.; "On the Parallax of Argelander's Star", Monthly Notices of the Royal Astronomical Society, December 1853, v.50, p.302, is a star in the constellatio ...

and

61 Cygni 61 Cygni is a binary star system in the constellation Cygnus, consisting of a pair of K-type dwarf stars that orbit each other in a period of about 659 years. Of apparent magnitude 5.20 and 6.05, respectively, they can be seen ...

, and the ninth-highest overall. This will move the star into

Tucana Tucana (The Toucan) is a constellation of stars in the southern sky, named after the toucan, a South American bird. It is one of twelve constellations conceived in the late sixteenth century by Petrus Plancius from the observations of Pieter D ...

around 2640. It figures directly between Alpha and Beta. Indus is home to one bright

binary star A binary star 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 using a telescope as separate stars, in wh ...

Theta Indi Theta Indi (θ Ind) is a binary star in the constellation Indus. Its apparent magnitude is 4.40 and it is approximately 98.8 light years away based on parallax. The smaller companion, B, has a spectral type of G0V (yellow main-sequence ...

is a binary star divisible in small amateur telescopes, 97 light-years from Earth. Its primary is a white star of magnitude 4.5 and its secondary is a white star of magnitude 7.0. It figures close to the hypotenuse of the right-angled triangle of Alpha, Beta and Delta, the three brightest stars of Indus.

T Indi T, or t, is the twentieth letter in the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''tee'' (pronounced ), plural ''tees''. It is deri ...

is the only bright

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 ...

in Indus. It is a semi-regular, deeply coloured

red giant A red giant is a luminous giant star of low or intermediate mass (roughly 0.3–8 solar masses ()) in a late phase of stellar evolution. The outer atmosphere is inflated and tenuous, making the radius large and the surface temperature around or ...

with a period of 11 months, 1900 light-years away. Its minimum magnitude is 7 and its maximum: 5. Galaxies include

NGC 7090 NGC 7090 is a spiral galaxy in the southern constellation of Indus located about 31 million light-years away. English astronomer John Herschel first observed this galaxy on 4 October 1834. The morphological class of NGC 7090 is Scd, i ...

and NGC 7049. All Sky Automated Survey for SuperNovae (ASAS-SN) in 2015 detected a

superluminous supernova A super-luminous supernova (SLSN, plural super luminous supernovae or SLSNe) is a type of stellar explosion with a luminosity 10 or more times higher than that of standard supernovae. Like supernovae, SLSNe seem to be produced by several mech ...

, named

ASASSN-15lh ASASSN-15lh ( supernova designation SN 2015L) is an extremely luminous astronomical transient event discovered by the All Sky Automated Survey for SuperNovae (ASAS-SN), with the appearance of a superluminous supernova event. It was first dete ...

(also designated

SN 2015L ASASSN-15lh ( supernova designation SN 2015L) is an extremely luminous astronomical transient event discovered by the All Sky Automated Survey for SuperNovae (ASAS-SN), with the appearance of a superluminous supernova event. It was first detect ...

). Based on the study conducted by Subo Dong and team from the Kavli Institute for Astronomy and Astrophysics (KIAA) at Peking University, it was approximately doubly luminous to any supernova detected, and at peak was almost 50 times more intrinsically luminous than 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 ...

. Its distance: approximately 3.82 gigalight-years, denoting an age approximately half that of the universe.

History

Johann Bayer - Uraniometria - Southern Birds

The constellation was created by

who made a fairly large celestial globe 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 ...

. The first depiction of this constellation in a celestial atlas followed 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 ''

'' of 1603. Plancius portrayed the figure as a nude male with three arrows in one hand and one in the other, as a native, lacking quiver and bow. It is among the twelve constellations introduced by Keyser and de Houtman, which first appeared on a celestial globe in 1598.

References

Sources

* * 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: Indus

* {{DEFAULTSORT:Indus (Constellation) Southern constellations Constellations listed by Petrus Plancius Astronomy in the Dutch Republic Dutch celestial cartography in the Age of Discovery 1590s in the Dutch Republic

Features

History

See also

References

Sources

External links