The thin disk is a structural component of spiral and S0-type galaxies, composed of stars, gas and dust. It is the main non-centre (e.g. galactic bulge) density, of such matter. That of the Milky Way is thought to have a scale height of around 300–400 parsecs (980–1,300 ly) in the vertical axis perpendicular to the disk,[1] and a scale length of around 2.5–4.5 kiloparsecs (8.2–14.7 kly) in the horizontal axis, in the direction of the radius.[2] For comparison, the Sun is 8 kiloparsecs (26 kly) out from the center. The thin disk contributes about 85% of the stars in the Galactic plane[3] and 95% of the total disk stars.[2] It can be set apart from the thick disk of a galaxy since the latter is composed of older population stars created at an earlier stage of the galaxy formation and thus has fewer heavy elements. Stars in the thin disk, on the other hand, are created as a result of gas accretion at the later stages of a galaxy formation and are on average more metal-rich.[4]
Edge on view of the Milky Way with several structures indicated (not to scale). The Thin disk is shown in green.
The thin disk contains stars with a wide range of ages and may be divided into a series of sub-populations of increasing age. Notwithstanding, it is considered to be considerably younger than the thick disk.[5]
Based upon the emerging science of nucleocosmochronology, the Galactic thin disk of the Milky Way is estimated to have been formed 8.8 ± 1.7 billion years ago.[6] It may have collided with a smaller satellite galaxy, causing the stars in the thin disk to be shaken up and creating the thick disk,[7] while the gas would have settled into the galactic plane and reformed the thin disk.[2]
Astronomers identify thick disc of older stars in nearby Andromeda galaxy
Populations & Components of the Milky Way
Referencesedit
^Bradley W. Carroll and Dale A. Ostlie, 2007, "An Introduction to Modern Astrophysics" Second Edition
^ abcSparke, Linda S.; Gallagher, John S. III (2007). Galaxies in the universe : an introduction (2. ed.). Cambridge: Cambridge Univ. Press. ISBN978-0521671866.
^Carlos Allende Prieto (Nov 2009). "The Stellar Population of the Thin Disk". Proceedings IAU Symposium. 265 (265): 304–312. arXiv:0911.3598. Bibcode:2010IAUS..265..304A. doi:10.1017/S1743921310000785. S2CID 118520855.
^"OpenStax CNX". cnx.org. Retrieved 31 January 2017.
^Bensby & Feltzing, "The Galactic thin and thick discs in the context of galaxy formation", arXiv:0908.3807
^Eduardo F. del Peloso a1a, Licio da Silva a1, Gustavo F. Porto de Mello and Lilia I. Arany-Prado (2005), "The age of the Galactic thin disk from Th/Eu nucleocosmochronology: extended sample" (Proceedings of the International Astronomical Union (2005), 1: 485-486 Cambridge University Press)
thin, disk, thin, disk, structural, component, spiral, type, galaxies, composed, stars, dust, main, centre, galactic, bulge, density, such, matter, that, milky, thought, have, scale, height, around, parsecs, vertical, axis, perpendicular, disk, scale, length, . The thin disk is a structural component of spiral and S0 type galaxies composed of stars gas and dust It is the main non centre e g galactic bulge density of such matter That of the Milky Way is thought to have a scale height of around 300 400 parsecs 980 1 300 ly in the vertical axis perpendicular to the disk 1 and a scale length of around 2 5 4 5 kiloparsecs 8 2 14 7 kly in the horizontal axis in the direction of the radius 2 For comparison the Sun is 8 kiloparsecs 26 kly out from the center The thin disk contributes about 85 of the stars in the Galactic plane 3 and 95 of the total disk stars 2 It can be set apart from the thick disk of a galaxy since the latter is composed of older population stars created at an earlier stage of the galaxy formation and thus has fewer heavy elements Stars in the thin disk on the other hand are created as a result of gas accretion at the later stages of a galaxy formation and are on average more metal rich 4 Edge on view of the Milky Way with several structures indicated not to scale The Thin disk is shown in green The thin disk contains stars with a wide range of ages and may be divided into a series of sub populations of increasing age Notwithstanding it is considered to be considerably younger than the thick disk 5 Based upon the emerging science of nucleocosmochronology the Galactic thin disk of the Milky Way is estimated to have been formed 8 8 1 7 billion years ago 6 It may have collided with a smaller satellite galaxy causing the stars in the thin disk to be shaken up and creating the thick disk 7 while the gas would have settled into the galactic plane and reformed the thin disk 2 See also editDisc galaxy Galaxy formation and evolution Galactic corona Galactic halo Galactic spheroid Spiral arm Thick diskExternal links editAstronomers identify thick disc of older stars in nearby Andromeda galaxy Populations amp Components of the Milky WayReferences edit Bradley W Carroll and Dale A Ostlie 2007 An Introduction to Modern Astrophysics Second Edition a b c Sparke Linda S Gallagher John S III 2007 Galaxies in the universe an introduction 2 ed Cambridge Cambridge Univ Press ISBN 978 0521671866 Carlos Allende Prieto Nov 2009 The Stellar Population of the Thin Disk Proceedings IAU Symposium 265 265 304 312 arXiv 0911 3598 Bibcode 2010IAUS 265 304A doi 10 1017 S1743921310000785 S2CID 118520855 OpenStax CNX cnx org Retrieved 31 January 2017 Bensby amp Feltzing The Galactic thin and thick discs in the context of galaxy formation arXiv 0908 3807 Eduardo F del Peloso a1a Licio da Silva a1 Gustavo F Porto de Mello and Lilia I Arany Prado 2005 The age of the Galactic thin disk from Th Eu nucleocosmochronology extended sample Proceedings of the International Astronomical Union 2005 1 485 486 Cambridge University Press Kasparova A 2016 The Diversity of Thick Galactic Discs Monthly Notices of the Royal Astronomical Society Letters 460 1 89 93 arXiv 1604 07624 Bibcode 2016MNRAS 460L 89K doi 10 1093 mnrasl slw083 Retrieved from https en wikipedia org w index php title Thin disk amp oldid 1174967920, wikipedia, wiki, book, books, library,
