Citizendia

Small Magellanic Cloud

NGC 346, part of the Small Magellanic Cloud.
Courtesy of NASA/ESA
Observation data (J2000 epoch)
ConstellationTucana
Right ascension00h 52m 44. The National Aeronautics and Space Administration ( NASA, ˈnæsə is an agency of the United States government, responsible for the nation's public space program The European Space Agency ( ESA) established in 1975 is an intergovernmental organisation dedicated to the exploration of space, currently with 17 member In Astronomy, an epoch is a moment in time used as a reference for the Orbital elements of a Celestial body. In Astronomy, an epoch is a moment in time used as a reference for the Orbital elements of a Celestial body. In common usage a constellation is a group of celestial bodies that are connected together in some arrangement typically stars to form a visible figure or picture Tucana is also an alternate name for the Tucano language. Tucana (tuːˈkɑːnə/ /-ˈkeɪnə/ /-ˈkænə ' Toucan ' is a southern Right ascension (abbrev RA; symbol α) is the Astronomical term for one of the two Coordinates of a point on the Celestial sphere 8s[1]
Declination-72° 49′ 43″[1]
Redshift158 ± 4 km/s[1]
Distance197 ± 9 kly (61 ± 3 kpc)[2]
TypeSB(s)m pec[1]
Apparent dimensions (V)5° 20′ × 3° 5′[1]
Apparent magnitude (V)2. In Astronomy, declination (abbrev dec or δ) is one of the two coordinates of the Equatorial coordinate system, the other being either In Physics and Astronomy, redshift occurs when Electromagnetic radiation – usually Visible light – emitted or reflected by The kilometre ( American spelling: kilometer) symbol km is a unit of Length in the Metric system, equal to one thousand A light-year or light year (symbol ly) is a unit of Length, equal to just under ten trillion Kilometres As defined by History The first direct measurements of an object at interstellar distances were undertaken by German Astronomer Friedrich Wilhelm Bessel in 1838 Galaxy morphological classification is a system used by Astronomers to divide galaxies into groups based on their visual appearance The angular diameter of an object as seen from a given position is the "visual diameter" of the object measured as an angle The apparent magnitude ( m) of a celestial body is a measure of its Brightness as seen by an observer on Earth, normalized to the value 7[1]
Notable featuresCompanion dwarf to the
Milky Way
Other designations
SMC,[1] NGC 292,[1] PGC 3085,[1] Nubecula Minor[1]
See also: Galaxy, List of galaxies

The Small Magellanic Cloud (SMC) is a dwarf galaxy[3]. The Milky Way (a translation of the Latin Via Lactea, in turn derived from the Greek Γαλαξίας (Galaxias sometimes referred to simply The New General Catalogue ( NGC) is the best-known catalogue of Deep sky objects in Amateur astronomy. The Catalogue of Principal Galaxies ( PGC) is an Astronomical catalogue published in 1989 that lists B1950 and J2000 Equatorial A galaxy is a massive gravitationally bound system consisting of Stars an Interstellar medium of gas and dust, and Dark matter This is a list of notable galaxies. List 4C 3711 Abell 1835 IR1916 AM 0644-741 A dwarf galaxy is a small Galaxy composed of up to several billion Stars a small number compared to our own Milky Way 's 200-400 billion stars It contains several hundred million stars. [4]

Some speculate that the SMC was once a barred spiral galaxy that was disrupted by the Milky Way to become somewhat irregular. A barred spiral galaxy is a Spiral galaxy with a central bar-shaped structure composed of Stars Bars are found in approximately half of all spiral galaxies An irregular galaxy is a Galaxy that does not fall into any of the regular classes of the Hubble sequence. [5] It still contains a central bar structure.

At a distance of about 200,000 light-years, it is one of the Milky Way's nearest neighbors. A light-year or light year (symbol ly) is a unit of Length, equal to just under ten trillion Kilometres As defined by It is also one of the most distant objects that can be seen with the naked eye.

With a mean declination of approximately -73 degrees, it can only be viewed from the Southern Hemisphere and the lower latitudes of the Northern Hemisphere. In Astronomy, declination (abbrev dec or δ) is one of the two coordinates of the Equatorial coordinate system, the other being either It is located in the constellation of Tucana and appears as a hazy, light patch in the night sky about 3 degrees across. In common usage a constellation is a group of celestial bodies that are connected together in some arrangement typically stars to form a visible figure or picture Tucana is also an alternate name for the Tucano language. Tucana (tuːˈkɑːnə/ /-ˈkeɪnə/ /-ˈkænə ' Toucan ' is a southern It looks like a detached piece of the Milky Way. Since it has a very low surface brightness, it is best viewed from a dark site away from city lights. Surface brightness is a concept used in Astronomy when describing extended Astronomical objects such as galaxies and Nebulae General

It forms a pair with the Large Magellanic Cloud (LMC), which is positioned a further 20 degrees to the east. The Large Magellanic Cloud (LMC is a nearby Satellite galaxy of our own galaxy the Milky Way. The Small Magellanic Cloud is a member of the Local Group. The Local Group is the group of galaxies that includes our galaxy the Milky Way.

Contents

Observation history

In the southern hemisphere, the Magellanic clouds have long been included in the lore of native inhabitants, including south sea islanders and indigenous Australians. The Pacific Ocean is the largest of the Earth 's Oceanic divisions Indigenous Australians are descendants of the first known human inhabitants of the Australian continent and its nearby islands. Persian astronomer Al Sufi labelled the larger of the two clouds as Al Bakr, the White Ox. The Persian Empire was a series of Iranian empires that ruled over the Iranian plateau, the original Persian homeland and beyond in Western Asia European sailors may have first noticed the clouds during the Middle Ages when they were used for navigation. Portuguese and Dutch sailors called them the Cape Clouds, a name that was retained for several centuries. Portugal, officially the Portuguese Republic (República Portuguesa is a country on the Iberian Peninsula. Holland is a region in the western part of the Netherlands. A maritime and economic power in the 17th century Holland today consists of the Dutch provinces of During the circumnavigation of the Earth by Ferdinand Magellan in 1519–22, they were described by Antonio Pigafetta as dim clusters of stars. Ferdinand Magellan (Fernão de Magalhães fɨɾˈnɐ̃ũ dɨ mɐgɐˈʎɐ̃ĩʃ Fernando de Magallanes (Spring 1480 &ndash April 27 1521 Mactan Island, Cebu Antonio Pigafetta (c 1491 was an Italian Scholar born in Vicenza. [6] In Johann Bayer's celestial atlas Uranometria, published in 1603, he named the smaller cloud, Nubecula Minor. Johann Bayer (1572 &ndash March 7, 1625) was a German Astronomer and Lawyer. Uranometria is the short title of a star atlas produced by Johann Bayer. [7] In Latin, Nubecula means a little cloud. Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. [8]

Between 1834 and 1838, John Frederick William Herschel made observations of the southern skies with his 20-foot reflector from the Royal Observatory at the Cape of Good Hope. Sir John Frederick William Herschel 1st Baronet KH, FRS ( March 7, 1792 &ndash May 11, 1871)was an The Cape of Good Hope ( Afrikaans: Kaap die Goeie Hoop, Kaap de Goede Hoop Cabo da Boa Esperança Persian Language: دماغه امید نیک While observing the Nubecula Minor, he described it as a cloudy mass of light with an oval shape and a bright center. Within the area of this cloud he catalogued a concentration of 37 nebulae and clusters. [9]

In 1891, Harvard College Observatory opened an observing station at Arequipa, Peru. The Harvard College Observatory (or HCO is an institution managing a complex of buildings and multiple instruments used for astronomical research by the Department of Astronomy Arequipa is a region in southwestern Peru. It is bordered by the Ica, Ayacucho, Apurímac and Cusco regions on the north the From 1893 and 1906, under the directorship of Solon Bailey, the 24-inch telescope at this site was used to photographically survey both the Large and Small Magellanic Clouds. [10] Henrietta Swan Leavitt, an astronomer at the Harvard College Observatory, used the plates from Arequipa to study of the variations in relative luminosity of stars in the SMC. Henrietta Swan Leavitt ( July 4 1868 &ndash December 12 1921) was an American Astronomer, and the Deaf daughter of a The Harvard College Observatory (or HCO is an institution managing a complex of buildings and multiple instruments used for astronomical research by the Department of Astronomy In 1908, the results Henrietta's study were published, which showed that a type of variable star called a "cluster variable", later called a cepheid variable after the prototype star Delta Cephei, showed a definite relationship between the variability period and the star's luminosity. For the astronomical object see Variable star. Variable Star is a 2006 novel written by Spider Robinson A Cepheid variable (pron ˈse-f(ē-id or ˈsē-f(ē-id or Cepheid is a member of a particular class of Variable stars notable for a fairly tight correlation Delta Cephei (δ Cep / δ Cephei is a Binary star system approximately 891 Light-years away in the Constellation of Cepheus (the King [11] This important period-luminosity relation allowed the distance to any other cepheid variable to be estimated in terms of the distance to the SMC. Hence, once the distance to the SMC was known with greater accuracy, Cepheid variables could be used as a standard candle for measuring the distances to other galaxies. A standard candle is an astronomical object that has a known Luminosity. [12]

Using this period-luminosity relation, in 1913 the distance to the SMC was first estimated by Ejnar Hertzsprung. Ejnar Hertzsprung ( October 8, 1873, Copenhagen &ndash October 21, 1967, Roskilde) was a Danish chemist First he measured thirteen nearby cepheid variables to find the absolute magnitude of a variable with a period of one day. In Astronomy, absolute magnitude (also known as absolute visual magnitude) is the Apparent magnitude an object would have if it were at a standard By comparing this to the periodicity of the variables as measured by Leavitt, he was able to estimate a distance of 10,000 parsecs (30,000 light years) between the Sun and the SMC. [13] This later proved to be a gross underestimate of the true distance, but it did demonstrate the potential usefulness of this technique. [14]

See also

References

  1. ^ a b c d e f g h i j NASA/IPAC Extragalactic Database. Galaxies other than the Milky Way are popular settings for creators of Science fiction, particularly those working with broad-scale Space opera settings The Large Magellanic Cloud (LMC is a nearby Satellite galaxy of our own galaxy the Milky Way. History The Magellanic Clouds were certainly known since the earliest times by the ancient Middle Eastern peoples NGC 265 is an Open cluster in the Small Magellanic Cloud, which is located in the Constellation Tucana. NGC 290 is an Open cluster in the Small Magellanic Cloud, which is located in the Constellation Tucana. NGC 346 is a Nebula located in the Small Magellanic Cloud that appears in the Constellation Tucana. Results for Small Magellanic Cloud. Retrieved on 2006-12-01. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 800 - Charlemagne judges the accusations against Pope Leo III in the Vatican
  2. ^ Hilditch, R. W. ; Howarth, I. D. ; Harries, T. J. (2005). "Forty eclipsing binaries in the Small Magellanic Cloud: fundamental parameters and Cloud distance". Monthly Notices of the Royal Astronomical Society 357 (1): 304-324.  
  3. ^ APOD: 2005 June 17 - The Small Cloud of Magellan
  4. ^ APOD: 2005 June 17 - The Small Cloud of Magellan
  5. ^ [1]
  6. ^ Westerlund, Bengt E. (1997). The Magellanic Clouds. Cambridge University Press. ISBN 0521480701.  
  7. ^ O'Meara, Stephen James (2002). The Caldwell Objects. Cambridge University Press. ISBN 0521827965.  
  8. ^ Lewis, Charlton Thomas; Kingery, Hugh Macmaster (1918). An elementary Latin dictionary. American Book Company.  
  9. ^ Herschel, John Frederick William (1849). Outlines of Astronomy. Philadelphia: Lea & Blanchard.  
  10. ^ Longair, Malcolm S. (2006). The Cosmic Century: A History of Astrophysics and Cosmology. Cambridge University Press. ISBN 0521474361.  
  11. ^ Leavitt, Henrietta S. (1908). "1777 variables in the Magellanic Clouds". Annals of Harvard College Observatory 60: 87–108.  
  12. ^ Aparicio, Antonio; Herrero, Artemio; Sánchez, Francisco (1998). Stellar Astrophysics for the Local Group. Cambridge University Press. ISBN 0521563275.  
  13. ^ Gribbin, John R. (1999). The Birth of Time: How Astronomers Measured the Age of the Universe. Yale University Press. ISBN 0300083467.  
  14. ^ Hoffleit, Dorrit (1992). "The Selector of Highlights: A Brief Biographical Sketch of Harlow Shapley". The Journal of the American Association of Variable Star Observers 21 (2): 151-156.  

External links

Dictionary

Small Magellanic Cloud

-proper noun

  1. (astronomy) An irregular galaxy, a satellite of Milky Way.
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