Coalsack Nebula

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Coalsack Nebula
Dark nebula
Part of the Coalsack Nebula.jpg
The Coalsack Nebula taken by the Wide Field Imager on the MPG/ESO 2.2-metre telescope [1]
Observation data: J2000.0 epoch
Right ascension 12h 50m
Declination −62° 30′
Distance180 [2]   pc
Apparent magnitude (V)
Apparent dimensions (V)7° × 5°
Constellation Crux
Physical characteristics
Radius 30–35 ly
Absolute magnitude (V)
Notable features
Designations Caldwell 99
See also: Lists of nebulae
Coal Sack Nebula UntitledCoalSackAutoRGB extra-1-2.jpg
Coal Sack Nebula

The Coalsack Nebula (Southern Coalsack, or simply theCoalsack) [3] is a dark nebula, which is visible to the naked eye as a dark patch obscuring part of the Milky Way east of Acrux (Alpha Crucis) in the constellation of Crux. [2]

Contents

General information

Historically any other dark cloud in the night sky was called coalsack. The Coalsack Nebula was juxtaposed in 1899 by Richard Hinckley Allen through naming the Northern Coalsack Nebula. [4]

The Coalsack Nebula covers nearly 7° by 5° and extends into the neighboring constellations Centaurus and Musca. [5] The first observation was reported by Vicente Yáñez Pinzón in 1499. [6] It was named "il Canopo fosco" (the dark Canopus) by Amerigo Vespucci and was also called "Macula Magellani" (Magellan's Spot) or "Black Magellanic Cloud" in opposition to the Magellanic Clouds. [6]

A depiction of the emu in the skyknown as weitj. The weitj in the sky is male, and you can see them guarding their eggs. During Makuru (the coldest and wettest time of the year, that falls across June and July), which is an Australian Aboriginal constellation consisting of dark clouds rather than of stars. The European constellation on the right is Crux, or the Southern Cross, and on the left is Scorpius. The head of the emu is the Coalsack. Emu public.jpg
A depiction of the emu in the sky known as weitj. The weitj in the sky is male, and you can see them guarding their eggs. During Makuru (the coldest and wettest time of the year, that falls across June and July), which is an Australian Aboriginal constellation consisting of dark clouds rather than of stars. The European constellation on the right is Crux, or the Southern Cross, and on the left is Scorpius. The head of the emu is the Coalsack.

In Australian Aboriginal astronomy, the Coalsack forms the head of the emu in the sky in several Aboriginal cultures. Amongst the Wardaman people, it is said to be the head and shoulders of a law-man watching the people to ensure they do not break traditional law. According to a legend reported by W. E. Harney, this being is called Utdjungon and only adherence to the tribal law by surviving tribe members could prevent him from destroying the world with a fiery star. [7] There is also a reference by Gaiarbau (1880) regarding the coalsacks replicating bora rings on Earth. These astronomical sites allowed the spirits to continue ceremony similar to their human counterparts on Earth. As bora grounds are generally located on the compass points north–south, the southern coal sack indicates the ceremonial ring.

In Inca astronomy this nebula was called Yutu, after a partridge-like South American bird, [8] or Tinamou. [9]

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<span class="mw-page-title-main">Constellation</span> Group of stars on the celestial sphere

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

<span class="mw-page-title-main">Crux</span> Constellation in the southern celestial hemisphere

Crux is a constellation of the southern sky that is centred on four bright stars in a cross-shaped asterism commonly known as the Southern Cross. It lies on the southern end of the Milky Way's visible band. The name Crux is Latin for cross. Even though it is the smallest of all 88 modern constellations, Crux is among the most easily distinguished as its four main stars each have an apparent visual magnitude brighter than +2.8. It has attained a high level of cultural significance in many Southern Hemisphere states and nations.

<span class="mw-page-title-main">Corona Australis</span> Constellation in the southern celestial hemisphere

Corona Australis is a constellation in the Southern Celestial Hemisphere. Its Latin name means "southern crown", and it is the southern counterpart of Corona Borealis, the northern crown. It is one of the 48 constellations listed by the 2nd-century astronomer Ptolemy, and it remains one of the 88 modern constellations. The Ancient Greeks saw Corona Australis as a wreath rather than a crown and associated it with Sagittarius or Centaurus. Other cultures have likened the pattern to a turtle, ostrich nest, a tent, or even a hut belonging to a rock hyrax.

<span class="mw-page-title-main">Dorado</span> Constellation in the southern sky

Dorado is a constellation in the Southern Sky. It was named in the late 16th century and is now one of the 88 modern constellations. Its name refers to the mahi-mahi, which is known as dorado ("golden") in Spanish, although it has also been depicted as a swordfish. Dorado contains most of the Large Magellanic Cloud, the remainder being in the constellation Mensa. The South Ecliptic pole also lies within this constellation.

<span class="mw-page-title-main">Grus (constellation)</span> Constellation in the southern celestial hemisphere

Grus is a constellation in the southern sky. Its name is Latin for the crane, a type of bird. It is one of twelve constellations conceived by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman. Grus first appeared on a 35-centimetre-diameter (14-inch) celestial globe published in 1598 in Amsterdam by Plancius and Jodocus Hondius and was depicted in Johann Bayer's star atlas Uranometria of 1603. French explorer and astronomer Nicolas-Louis de Lacaille gave Bayer designations to its stars in 1756, some of which had been previously considered part of the neighbouring constellation Piscis Austrinus. The constellations Grus, Pavo, Phoenix and Tucana are collectively known as the "Southern Birds".

<span class="mw-page-title-main">Hydrus</span> Constellation in the southern celestial hemisphere

Hydrus is a small constellation in the deep southern sky. It was one of twelve constellations created by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman and it first appeared on a 35-cm (14 in) diameter celestial globe published in late 1597 in Amsterdam by Plancius and Jodocus Hondius. The first depiction of this constellation in a celestial atlas was in Johann Bayer's Uranometria of 1603. The French explorer and astronomer Nicolas Louis de Lacaille charted the brighter stars and gave their Bayer designations in 1756. Its name means "male water snake", as opposed to Hydra, a much larger constellation that represents a female water snake. It remains below the horizon for most Northern Hemisphere observers.

<span class="mw-page-title-main">Sagittarius (constellation)</span> Zodiac constellation in the southern celestial hemisphere

Sagittarius is one of the constellations of the zodiac and is located in the Southern celestial hemisphere. It is one of the 48 constellations listed by the 2nd-century astronomer Ptolemy and remains one of the 88 modern constellations. Its old astronomical symbol is (♐︎). Its name is Latin for "archer". Sagittarius is commonly represented as a centaur drawing a bow. It lies between Scorpius and Ophiuchus to the west and Capricornus and Microscopium to the east.

<span class="mw-page-title-main">Tucana</span> Constellation in the southern celestial hemisphere

Tucana 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 Dirkszoon Keyser and Frederick de Houtman. Tucana first appeared on a 35-centimetre-diameter (14 in) celestial globe published in 1598 in Amsterdam by Plancius and Jodocus Hondius and was depicted in Johann Bayer's star atlas Uranometria of 1603. French explorer and astronomer Nicolas Louis de Lacaille gave its stars Bayer designations in 1756. The constellations Tucana, Grus, Phoenix and Pavo are collectively known as the "Southern Birds".

<span class="mw-page-title-main">Triangulum Australe</span> Constellation in the southern celestial hemisphere

Triangulum Australe is a small constellation in the far Southern Celestial Hemisphere. Its name is Latin for "the southern triangle", which distinguishes it from Triangulum in the northern sky and is derived from the acute, almost equilateral pattern of its three brightest stars. It was first depicted on a celestial globe as Triangulus Antarcticus by Petrus Plancius in 1589, and later with more accuracy and its current name by Johann Bayer in his 1603 Uranometria. The French explorer and astronomer Nicolas Louis de Lacaille charted and gave the brighter stars their Bayer designations in 1756.

<span class="mw-page-title-main">Vela (constellation)</span> Constellation in the southern celestial hemisphere

Vela is a constellation in the southern sky, which contains the Vela Supercluster. Its name is Latin for the sails of a ship, and it was originally part of a larger constellation, the ship Argo Navis, which was later divided into three parts, the others being Carina and Puppis. With an apparent magnitude of 1.8, its brightest star is the hot blue multiple star Gamma Velorum, one component of which is the closest and brightest Wolf-Rayet star in the sky. Delta and Kappa Velorum, together with Epsilon and Iota Carinae, form the asterism known as the False Cross. 1.95-magnitude Delta is actually a triple or quintuple star system.

<span class="mw-page-title-main">Dark nebula</span> Type of interstellar cloud that obscures visible light

A dark nebula or absorption nebula is a type of interstellar cloud, particularly molecular clouds, that is so dense that it obscures the visible wavelengths of light from objects behind it, such as background stars and emission or reflection nebulae. The extinction of the light is caused by interstellar dust grains in the coldest, densest parts of molecular clouds. Clusters and large complexes of dark nebulae are associated with Giant Molecular Clouds. Isolated small dark nebulae are called Bok globules. Like other interstellar dust or material, the things it obscures are visible only using radio waves in radio astronomy or infrared in infrared astronomy.

<span class="mw-page-title-main">Musca</span> Constellation in the southern celestial hemisphere

Musca is a small constellation in the deep southern sky. It was one of 12 constellations created by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman, and it first appeared on a celestial globe 35 cm (14 in) in diameter published in 1597 in Amsterdam by Plancius and Jodocus Hondius. The first depiction of this constellation in a celestial atlas was in Johann Bayer's Uranometria of 1603. It was also known as Apis for 200 years. Musca remains below the horizon for most Northern Hemisphere observers.

<span class="mw-page-title-main">Pavo (constellation)</span> Constellation in the southern celestial hemisphere

Pavo is a constellation in the southern sky whose name is Latin for 'peacock'. Pavo first appeared on a 35-cm (14 in) diameter celestial globe published in 1598 in Amsterdam by Petrus Plancius and Jodocus Hondius and was depicted in Johann Bayer's star atlas Uranometria of 1603, and was likely conceived by Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman. French explorer and astronomer Nicolas-Louis de Lacaille gave its stars Bayer designations in 1756. The constellations Pavo, Grus, Phoenix and Tucana are collectively known as the "Southern Birds".

<span class="mw-page-title-main">Tarantula Nebula</span> H II region in the constellation Dorado

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<span class="mw-page-title-main">Lagoon Nebula</span> Emission nebula in Sagittarius

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Australian Aboriginal astronomy has been passed down orally, through ceremonies, and in their artwork of many kinds. The astronomical systems passed down thus show a depth of understanding of the movement of celestial objects which allowed them to use them as a practical means for creating calendars and for navigating across the continent and waters of Australia. There is a diversity of astronomical traditions in Australia, each with its own particular expression of cosmology. However, there appear to be common themes and systems between the groups. Due to the long history of Australian Aboriginal astronomy, the Aboriginal peoples have been described as "world's first astronomers" on several occasions.

<span class="mw-page-title-main">NGC 2867</span> Planetary nebula in the constellation Carina

NGC 2867 is an elliptical Type II planetary nebula in the southern constellation of Carina, just over a degree to the NNW of the star Iota Carinae. It was discovered by John Herschel on April 1, 1834. Herschel initially thought he might have found a new planet, but on the following night he checked again and discovered it had not moved. The nebula is located at a distance of 7,270 light-years from the Sun.

<span class="mw-page-title-main">NGC 6884</span> Planetary nebula in the constellation in the constellation Cygnus

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<span class="mw-page-title-main">Great Rift (astronomy)</span> Interstellar clouds of cosmic dust

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Indigenous astronomy is the name given to the use and study of astronomical subjects and their movements by indigenous groups. This field encompasses culture, traditional knowledge, and astronomy. Astronomy has been practised by indigenous groups to create astronomical calendars which inform on weather, navigation, migration, agriculture, and ecology. Alongside calendric uses, constellations have names and stories that inform ceremony and social structures holding specific and deep cultural meanings for respective indigenous groups.

References

  1. "A Cosmic Sackful of Black Coal" . Retrieved 15 October 2015.
  2. 1 2 Franco, G.P.A. (2000). "Interstellar Na I D lines towards the Southern Coalsack". Monthly Notices of the Royal Astronomical Society. 315 (3): 611–621. Bibcode:2000MNRAS.315..611F. doi: 10.1046/j.1365-8711.2000.03434.x .
  3. "Coalsack Nebula". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2018-09-30.
  4. O'Meara, Stephen James (2012-04-23). "Where is the Northern Coalsack?". Astronomy.com. Retrieved 2023-02-10.
  5. Darling, David J. (2004). The universal book of astronomy: from the Andromeda Galaxy to the zone of avoidance. Hoboken, New Jersey: Wiley. p. 351. ISBN   0471265691.
  6. 1 2 "The Coalsack and the Southern Cross". ESO . 3 December 2009. Retrieved 1 October 2018.
  7. Songs of the Songmen, 28–30.
  8. James B. Kaler (2002). The Hundred Greatest Stars. New York: Springer Science & Business Media. p. 5. ISBN   978-0-387-95436-3.
  9. A. F. Aveni, ed. (2010). Archaeoastronomy in the New World : American primitive astronomy : proceedings of an international conference held at Oxford University, September, 1981. Cambridge: Cambridge University Press. ISBN   978-0521125475.