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Encyclopedia > Sagittarius Dwarf Elliptical Galaxy
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Sagittarius Dwarf Elliptical Galaxy
Galaxy listing of galaxies

The Sagittarius Dwarf Elliptical Galaxy (Sag DEG) is a satellite galaxy of the Milky Way Galaxy. Roughly 10,000 light years (58.7 quadrillion miles) in diameter, it is currently about 70,000 light years (411.2 quadrillion miles) from Earth and travelling in a polar orbit at a distance of about 50,000 light years (293.7 quadrillion miles) from the core of the Milky Way (about a third the distance of the Large Magellanic Cloud). Not to be confused with the Sagittarius Dwarf Irregular Galaxy (Sag DIG). NGC 4414, a typical spiral galaxy in the constellation Coma Berenices, is about 56,000 light years in diameter and approximately 60 million light years distant. ... NGC 4414, a typical spiral galaxy in the constellation Coma Berenices, is about 56,000 light years in diameter and approximately 60 million light years distant. ... The Milky Way (a translation of the Latin Via Lactea, in turn derived from the Greek Galaxia Kuklos; or simply the Galaxy) is a barred spiral galaxy in the Local Group, and has special significance to humanity as the location of the solar system, which is located near the Orion... Earth, also known as the Earth, Terra, and (mostly in the 19th century) Tellus, is the third-closest planet to the Sun. ... The Large Magellanic Cloud (also known as LMC) is a dwarf galaxy that is in orbit around our own Milky Way galaxy. ... The Sagittarius Dwarf Irregular Galaxy or SagDIG is a dwarf galaxy in the constellation of Sagittarius. ...


Although it is one of the closest companion galaxies to the Milky Way, it is on the opposite side of the galactic core from Earth, and consequently is very faint, although it covers a large area of the sky. It was only discovered in 1994, by R. Ibata, M. Irwin, and G. Gilmore; was immediately recognized as being the nearest known neighbour to our Milky Way. Sag DEG appears to be an older galaxy, with little interstellar dust and composed largely of Population II stars, older and metal-poor compared to the Milky Way. The Galactic Center is the rotational center of the Milky Way galaxy. ... 1994 was a common year starting on Saturday of the Gregorian calendar, and was designated the International year of the Family. ... Stars can be grouped into two general types called Population I and Population II. The criteria for classification include space velocity, location in the galaxy, age, chemical composition, and differences in distribution on the Hertzsprung-Russell diagram. ...

Sagittarius Dwarf Elliptical Galaxy
Observation data
(Epoch J2000.0)
Type elliptical
Right ascension 18h 55m
Declination -30° 30′
Distance 80,000 ly
Apparent magnitude (V) -
Apparent dimensions (V) 190 × 490 arcmins
Constellation -
Physical characteristics
Radius 5,000 ly
Absolute magnitude (V) -
Notable features it is heading for a collision with the Milky Way
Other designations None

Based on its current trajectory, Sag DEG is poised to pass through the galactic disc of the Milky Way within the next hundred million years, and is in the process of slowly being absorbed into the larger galaxy. In astronomy, an epoch is a moment in time for which celestial coordinates or orbital elements are specified. ... The Hubble sequence is a classification of galaxy types developed by Edwin Hubble in 1936. ... Right ascension (RA; symbol α: Greek letter alpha) is the astronomical term for one of the two coordinates of a point on the celestial sphere when using the equatorial coordinate system. ... In astronomy, declination (dec) is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. ... (Redirected from 1 E22 m) Categories: Orders of magnitude (length) ... Light year, a measure of distant Lightyear (band), a ska-punk band from the UK Buzz Lightyear, a character in the animated film Toy Story. ... The apparent magnitude (m) of a star, planet or other heavenly body is a measure of its apparent brightness; that is, the amount of light received from the object. ... A minute of arc, arcminute, or MOA is a unit of angular measurement, equal to one sixtieth (1/60) of one degree. ... -1... Light year, a measure of distant Lightyear (band), a ska-punk band from the UK Buzz Lightyear, a character in the animated film Toy Story. ... In astronomy, absolute magnitude is the apparent magnitude, m, an object would have if it were at a standardized distance away. ... A NASA artists conception of what the Milky Way would look like if seen off-axis. ...


The exact history and future of Sag DEG is very much under debate.


At first, many astronomers thought that the SagDEG had already reached an advanced state of destruction, so that a large part of its original matter was already mixed with that of the Milky Way. However, Sag DEG still has coherence as a dispersed elongated ellipse, and appears to move in a roughly polar orbit around the Milky Way as close as 50,000 light years from the galactic core. Although it may have begun as a ball of stars before falling towards the Milky Way, SagDEG is now being torn apart by immense tidal forces over hundreds of millions of years. Numerical simulations suggest that stars ripped out from the dwarf would be spread out in long streamers along its path, which were subsequently detected.


However, some astronomers contend that Sag DEG has been in orbit around the Milky Way for some billions of years, and has already orbited around it around ten times. Its ability to retain some coherence despite such strains would indicate an unusually high concentration of dark matter within that galaxy. In cosmology, dark matter refers to hypothetical matter particles, of unknown composition, that do not emit enough electromagnetic radiation to be detected directly, but whose presence can be inferred from gravitational effects on visible matter such as stars and galaxies. ...


On the other hand, others note the similarity of star types between Sag DEG and the Large Magellanic Cloud, arguing that it has recently gone into orbit about our galaxy having somehow become detached. The Large Magellanic Cloud (also known as LMC) is a dwarf galaxy that is in orbit around our own Milky Way galaxy. ...


SagDEG has a globular cluster, M54. Globular Cluster M54 (also known as Messier Object 54, Messier 54, M54, or NGC 6715) is a globular cluster in the Sagittarius Dwarf Elliptical Galaxy (SagDEG). ...


From its discovery until 2003, it was considered to be the closest outside galaxy to Earth, but since then has been overtaken by the newly discovered Canis Major Dwarf Galaxy. 2003(MMIII) is a common year starting on Wednesday of the Gregorian calendar. ... The Canis Major Dwarf Galaxy is located in the same part of the sky as the constellation of Canis Major. ...


Sag DEG should not be confused with SagDIG, the Sagittarius Dwarf Irregular Galaxy, a small galaxy nearly 4 million light years distant. The Sagittarius Dwarf Irregular Galaxy or SagDIG is a dwarf galaxy in the constellation of Sagittarius. ...


See also

Categories: Stub | Globular clusters | NGC objects | Milky Way Galaxy | Dwarf galaxies | Local Group | Milky Way Subgroup ... Globular Cluster M54 (also known as Messier Object 54, Messier 54, M54, or NGC 6715) is a globular cluster in the Sagittarius Dwarf Elliptical Galaxy (SagDEG). ...

External links

  • SagDEG (SEDS)
  • SagDEG at solstation.com

  Results from FactBites:
 
Sagittarius - Wikipedia, the free encyclopedia (628 words)
Sagittarius lies between Scorpius to the west and Capricornus to the east.
Sagittarius has the rough appearance of a stick-figure archer drawing its bow, and when including the fainter stars, appears to have a horse-like body [3].
The symbol for Sagittarius is the centaur or archer.
  More results at FactBites »

 
 

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