Editing Plummer model (section)

The '''Plummer model''' or '''Plummer sphere''' is a density law that was first used by [[Henry Crozier Keating Plummer|H. C. Plummer]] to fit observations of [[globular cluster]]s.<ref>Plummer, H. C. (1911), [http://adsabs.harvard.edu/abs/1911MNRAS..71..460P On the problem of distribution in globular star clusters], ''[[Monthly Notices of the Royal Astronomical Society|Mon. Not. R. Astron. Soc.]]'' '''71''', 460.</ref> It is now often used as [[toy model]] in [[N-body simulation]]s of stellar systems.