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 A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

long, tilted away from the

galactic plane The galactic plane is the plane on which the majority of a disk-shaped galaxy's mass lies. The directions perpendicular to the galactic plane point to the galactic poles. In actual usage, the terms ''galactic plane'' and ''galactic poles'' usual ...

by about 16–20 degrees. It contains many O- and B-type stars, amounting to the nearest star-forming regions of the local

spiral arm Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

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 It has recently been largely superseded in definition by the Radcliffe wave and ''Split'' linear structures.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 a ...

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 a ...

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 Lacerta is one of the 88 modern constellations defined by the International Astronomical Union. Its name is Latin for lizard. A small, faint constellation, it was defined in 1687 by the astronomer Johannes Hevelius. Its brightest stars form a "W" ...

adjacent parts – break for constellations including Sagittarius with the galactic bar/bulge/center – then

Scorpius Scorpius is a zodiac constellation located in the Southern celestial hemisphere, where it sits near the center of the Milky Way, between Libra to the west and Sagittarius to the east. Scorpius is an ancient constellation that pre-dates the Gre ...

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 Centaurus is a bright constellation in the southern sky. One of the largest constellations, Centaurus was included among the 48 constellations listed by the 2nd-century astronomer Ptolemy, and it remains one of the 88 modern constellations. ...

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; then

Carina Carina may refer to: Places Australia * Carina, Queensland, a suburb in Brisbane * Carina Heights, Queensland, a suburb in Brisbane * Carina, Victoria, a locality in Mildura Serbia * Carina, Osečina, a village in the Kolubara District ...

- 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 regions and OB associations that make up this region include the Orion Nebula 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 A molecular cloud, sometimes called a stellar nursery (if star formation is occurring within), is a type of interstellar cloud, the density and size of which permit absorption nebulae, the formation of molecules (most commonly molecular hydrogen ...

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