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The | In [[astronomy]], the '''Kennicutt–Schmidt''' (or simply the '''Schmidt \lLaw''') is an empirical relation between the gas density and star formation rate (SFR) in a given region. The relation was first examined by [[Maarten Schmidt]] in a 1959 paper in which he proposed that the SFR surface density scales as some positive power <math>n</math> of the local gas surface density.<ref name="schmidt59" /> i.e. | ||
:<math>\Sigma_{SFR} \propto (\Sigma_{gas})^n</math>. | |||
In general the SFR surface density <math>(\Sigma_{SFR})</math> is in units of solar masses per year per square parsec <math>(M_\odot ~\textrm{ yr}^{-1} \textrm{ pc}^{-2})</math> and the gas surface density in grams per square parsec <math>(\textrm{g}~\textrm{pc}^{-2})</math>. Using an analysis of gaseous helium and young stars in the solar neighborhood, the local density of [[white dwarfs]] and their [[luminosity function]], and the local helium density, Schmidt suggested a value of <math>n \approx 2</math> (and very likely between 1 and 3). All of the data used were gathered from the Milky Way, and specifically the solar-neighborhood. | |||
More recently, [[Robert Kennicutt]] examined the connection between gas density and SFR for nearly 100 nearby galaxies to estimate a value of <math>n = 1.4 \pm 0.15</math>.<ref name="kennicutt98" /> | |||
==References== | |||
{{Reflist|refs= | |||
*<ref name="schmidt59">{{Cite journal | author = Schmidt, Maarten | year = 1959 | month = | title = The Rate of Star Formation | journal = The Astrophysical Journal | volume = 129 | issue = | pages = 243 | doi=10.1086/146614 | bibcode=1959ApJ...129..243S}}</ref> | |||
</ref> | |||
*<ref name="kennicutt98">{{Cite journal | author = Kennicutt, Robert C., Jr. | year = 1998 | month = | title = The Global Schmidt Law in Star-forming Galaxies | journal = The Astrophysical Journal | volume = 498 | issue = | pages = 541 | doi = 10.1086/305588 | bibcode=1998ApJ...498..541K|arxiv = astro-ph/9712213 }}</ref> | |||
</ref> | |||
}} | |||
{{DEFAULTSORT:Kennicutt-Schmidt law}} | |||
[[Category:Stellar astronomy]] | |||
[[Category:Galaxies]] | |||
[[Category:Star formation]] |
Latest revision as of 17:16, 26 October 2013
In astronomy, the Kennicutt–Schmidt (or simply the Schmidt \lLaw) is an empirical relation between the gas density and star formation rate (SFR) in a given region. The relation was first examined by Maarten Schmidt in a 1959 paper in which he proposed that the SFR surface density scales as some positive power of the local gas surface density.[1] i.e.
In general the SFR surface density is in units of solar masses per year per square parsec and the gas surface density in grams per square parsec . Using an analysis of gaseous helium and young stars in the solar neighborhood, the local density of white dwarfs and their luminosity function, and the local helium density, Schmidt suggested a value of (and very likely between 1 and 3). All of the data used were gathered from the Milky Way, and specifically the solar-neighborhood.
More recently, Robert Kennicutt examined the connection between gas density and SFR for nearly 100 nearby galaxies to estimate a value of .[2]
References
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