The Large Sagittarius Star Cloud is the brightest visible region of 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 A galaxy is a system of stars, stellar remnants, interstellar gas, dust, dark matter, bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. ...

, a portion of the central

bulge __NOTOC__ Bulge may refer to: Astronomy and geography *Bulge (astronomy), a tightly packed group of stars at the center of a spiral galaxy *Equatorial bulge, a bulge around the equator of a planet due to rotation *Tharsis bulge, vast volcanic pla ...

seen around the thick dust of the Great Rift which lines the northwest edge. It should not be confused with the nearby

Small Sagittarius Star Cloud The Small Sagittarius Star Cloud (also known as Messier 24 and IC 4715) is a star cloud in the constellation of Sagittarius approximately 600 light years wide, which was catalogued by Charles Messier in 1764. It should not be confused with the ...

, which lies about 10° to the north. The

star cloud Star clusters are large groups of stars. Two main types of star clusters can be distinguished: globular clusters are tight groups of ten thousand to millions of old stars which are gravitationally bound, while open clusters are more loosely clust ...

stretches several degrees north from the star

Gamma Sagittarii The Bayer designation γ Sagittarii (Gamma Sagittarii) is shared by two stars in the 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, ...

and is considered a splendid sight in binoculars - "a bright glow with multitudes of momentarily resolved star-sparks". To the naked eye, the Cloud appears bright and smooth, and is said to resemble a puff of "steam" escaping from the spout of the Sagittarius "Teapot" asterism.

Properties

The Large Sagittarius Star Cloud is the innermost galactic structure that can be observed in visible wavelengths, and the most distant portion of the Milky Way that can be seen with unaided eyes. Being depleted of the gas and dust from which new stars form, the region contains no young blue stars. Instead, the brightest stars are K-type orange giants, which is why the Cloud has a yellowish tint on color photos. The Galactic Center, which is obscured at visible wavelengths due to interstellar dust, lies about two degrees west of the Cloud.

Features

Superimposed upon the Large Sagittarius Star Cloud is the bright

open cluster An open cluster is a type of star cluster made of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way galaxy, and ...

NGC 6520. Close by to the west is the small dark nebula Barnard 86, a Bok globule described by

Edward Emerson Barnard Edward Emerson Barnard (December 16, 1857 – February 6, 1923) was an American astronomer. He was commonly known as E. E. Barnard, and was recognized as a gifted observational astronomer. He is best known for his discovery of the high proper mo ...

as “a drop of ink on the luminous sky”. To the east of this pair lies the globular cluster NGC 6540. The southern end of the Cloud features a pair of globular clusters,

NGC 6522 NGC 6522 is a globular cluster in the constellation Sagittarius. It is apparent magnitude 8.3, and diameter 16.4 arc minutes, and class VI with stars 16th magnitude and dimmer. It was discovered by William Herschel on June 24, 1784. It is cente ...

and

NGC 6528 NGC 6528 is a globular cluster in the constellation Sagittarius, and is listed in the New General Catalogue. It has an apparent magnitude of about 11 and a diameter of about 16 arcminutes, and its Shapley-Sawyer Concentration Class is V, contain ...

, both of which lie within

Baade's Window Baade's Window is an area of the sky with relatively low amounts of cosmic dust, interstellar dust along the line of sight from Earth. This area is considered an observational "window" as the normally obscured Galactic Center of the Milky Way is ...

, an area especially clear of interstellar dust.

Astronomical Survey

The

Sagittarius Window Eclipsing Extrasolar Planet Search The Sagittarius Window Eclipsing Extrasolar Planet Search, or SWEEPS, was a 2006 astronomical survey project using the Hubble Space Telescope's Advanced Camera for Surveys - Wide Field Channel to monitor 180,000 stars for seven days to detect ext ...

(SWEEPS) was a 2006

astronomical survey An astronomical survey is a general map or image of a region of the sky (or of the whole sky) that lacks a specific observational target. Alternatively, an astronomical survey may comprise a set of images, spectra, or other observations of obje ...

project using 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 ...

to monitor 180,000 stars for seven days to detect

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 ...

References

External links

* * * {{cite web, title=The Large Sagittarius Star Cloud , url=http://spaceref.com/astronomy/the-large-sagittarius-star-cloud.html Star clouds Milky Way Sagittarius (constellation)

Properties

Features

Astronomical Survey

See also

References

External links