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TheGould Belt is a local ring of stars in theMilky Way, tilted away from thegalactic plane by about 16–20 degrees, first reported byJohn Herschel andBenjamin Gould in the 19th century.[1] It contains manyO- and B-type stars, and many of the neareststar-forming regions of the localOrion Arm, to which theSun belongs. The relative proximity of these star-forming regions spurred theGould Belt Survey project to determine what caused them.
It was long speculated that the belt was a physical structure in the galactic disk, but data from theGaia survey indicate that several of its star-forming regions belong instead to the separateRadcliffe wave andsplit[2] linear structures in the Orion Arm, and that the circular appearance of the belt results mostly from the projection of these structures onto thecelestial sphere.[3]
The belt contains bright, young stars which formed about 30 to 50 million years ago in several constellations.[4][5][6] These lie along agreat circle slightly inclined to the Milky Way. including (in order from Taurus):Taurus,Perseus,Cepheus,Lacerta,Scorpius,Lupus, southernCentaurus,Crux (the Southern Cross),Carina,Vela,Puppis,Canis Major, andOrion.
Star-forming regions andOB associations that make up this region include theOrion Nebula and the Orion molecular clouds, theScorpius–Centaurus OB association, Cepheus OB2, Perseus OB2, and theTaurus–Auriga molecular clouds. The Serpens molecular cloud containing star-forming regionsW40 andSerpens 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 ofdark matter collided with themolecular cloud in our region. There is also evidence for similar Gould belts in other galaxies.[7][8]
| Included | Earth →Solar System →Local Interstellar Cloud →Local Bubble →Gould Belt →Orion Arm →Milky Way →Milky Way subgroup →Local Group→Local Sheet→Local Volume→Virgo Supercluster→Laniakea Supercluster →Pisces–Cetus Supercluster Complex →Local Hole →Observable universe →Universe Each arrow (→) may be read as "within" or "part of". |
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