The Gould Belt is a local, partial ring of

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

s in 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 ...

, about 3,000 light-years long, tilted away from the galactic plane by about 16–20 degrees. It contains many O- and B-type stars, amounting to the nearest

star-forming region Star formation is the process by which dense regions within molecular clouds in The "medium" is present further soon.-->interstellar space

s of the local spiral arm, to which the Sun belongs. It has recently been largely superseded in definition by the Radcliffe wave and ''Split'' linear structures. The Belt, as formed, and traditionally defined, runs for much less than one tenth of the extent of the local circumference of the galaxy, meaning in

galactic coordinates The galactic coordinate system is a celestial coordinate system in spherical coordinates, with the Sun as its center, the primary direction aligned with the approximate center of the Milky Way Galaxy, and the fundamental plane parallel to an ap ...

it spans a narrow range of

galactic longitude The galactic coordinate system is a celestial coordinate system in spherical coordinates, with the Sun as its center, the primary direction aligned with the approximate center of the Milky Way Galaxy, and the fundamental plane parallel to an ap ...

s. The coalescence and/or inception of new stars which cluster within it, nearby, are dated to about 30–50 million years ago. Beyond suspected prior

nebulosity A nebula ('cloud' or 'fog' in Latin; pl. nebulae, nebulæ or nebulas) is a distinct luminescent part of interstellar medium, which can consist of ionized, neutral or molecular hydrogen and also cosmic dust. Nebulae are often star-forming regio ...

of many of the younger stars, and the relative concentration of gas mentioned in the Radcliffe Wave, the factors that have led to the Gould Belt's unbroken nature and concentration are far from fully understood –

dark matter Dark matter is a hypothetical form of matter thought to account for approximately 85% of the matter in the universe. Dark matter is called "dark" because it does not appear to interact with the electromagnetic field, which means it does not ab ...

has in some leading literature been posited as causatory, in

astrophysics Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. As one of the founders of the discipline said, Astrophysics "seeks to ascertain the nature of the h ...

, as somehow intrinsic to the high density of recent stellar formation seen. It is named after

Benjamin Gould Benjamin Apthorp Gould (September 27, 1824 – November 26, 1896) was a pioneering American astronomer. He is noted for creating the ''Astronomical Journal'', discovering the Gould Belt, and for founding of the Argentine National Observatory an ...

, who identified it in 1879. The belt contains bright, young stars in many constellations. These are, in order, going south-west then north-west (after Crux):

Perseus In Greek mythology, Perseus (Help:IPA/English, /ˈpɜːrsiəs, -sjuːs/; Greek language, Greek: Περσεύς, Romanization of Greek, translit. Perseús) is the legendary founder of Mycenae and of the Perseid dynasty. He was, alongside Cadmus ...

, then Cepheus- Lacerta adjacent parts – break for constellations including Sagittarius with the galactic bar/bulge/center – then Scorpius,

Lupus Lupus, technically known as systemic lupus erythematosus (SLE), is an autoimmune disease in which the body's immune system mistakenly attacks healthy tissue in many parts of the body. Symptoms vary among people and may be mild to severe. Comm ...

, southern Centaurus,

Crux 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 c ...

(the Southern Cross). This part thus includes the

Scorpius–Centaurus association The Scorpius–Centaurus association (sometimes called Sco–Cen or Sco OB2) is the nearest OB association to the Sun. This stellar association is composed of three subgroups (Upper Scorpius, Upper Centaurus–Lupus, and Lower Centaurus–Crux) ...

; then Carina- Vela-

Puppis Puppis is a constellation in the southern sky. Puppis, the Latin translation of "poop deck", was originally part of an over-large constellation Argo Navis (the ship of Jason and the Argonauts), which centuries after its initial description, was ...

adjacent parts,

Canis Major Canis Major is a constellation in the Southern Celestial Hemisphere, southern celestial hemisphere. In the second century, it was included in Ptolemy's 48 constellations, and is counted among the 88 modern constellations. Its name is Latin fo ...

, Orion, which spans the celestial equator, and leaves a brief, fewer young-stars part of the outer Milky Way plane leading back to Perseus. The dense plane of the Milky Way, looking slightly and fully tangentially, and then outward, makes luminosity and dust in forming the central axis for its course, though stays in Scorpius, not passing noticeably into Lupus and stays to one side of Orion, for instance. The belt thus meanders slightly east and west of its main course, corresponding with its tilt to, or maximal deviation from, the visible, star-rich galactic plane.

Overview

Star-forming region Star formation is the process by which dense regions within molecular clouds in The "medium" is present further soon.-->interstellar space

s and OB associations that make up this region include the

Orion Nebula The Orion Nebula (also known as Messier 42, M42, or NGC 1976) is a diffuse nebula situated in the Milky Way, being south of Orion's Belt in the constellation of Orion. It is one of the brightest nebulae and is visible to the naked eye in the nig ...

and the Orion molecular clouds, the Scorpius–Centaurus OB association, Cepheus OB2, Perseus OB2, and the Taurus–Auriga molecular clouds. The Serpens molecular cloud containing star-forming regions W40 and Serpens south is often included in Gould Belt surveys, but is not formally part of the Gould Belt due to its greater distance. A theory proposed around 2009 suggests that the Gould Belt formed about 30 million years ago when a blob of

collided with the molecular cloud in our region. There is also evidence for similar Gould belts in other galaxies.

References

External links

Map of the Gould Belt3D evolution of the Gould Belt
{{Portal bar, Astronomy, Space Open clusters Milky Way ?

Overview

See also

References

External links