What is Eddington limit?
The '''Eddington limit''', or '''Eddington luminosity''' was first worked out by [[Arthur Eddington]]. It is a natural limit to the normal [[luminosity]] of stars. The state of balance is a [[hydrostatic equilibrium]]. When a star exceeds the Eddington limit, it loses [[mass]] with a very intense radiation-driven [[stellar wind]] from its outer layers. Eddington's models treated a star as a [[sphere]] of gas held up against [[gravity]] by internal thermal pressure. Eddington showed that radiation pressure was necessary to prevent collapse of the sphere.<ref>Eddington A.S. 1926. ''The internal constitution of stars''. Cambridge University Press. {{ISBN|0-521-33708-9}}</ref> Most massive stars have luminosities far below the Eddington luminosity, so their winds are mostly driven by the less intense line absorption.<ref>{{cite journal |bibcode=2008AIPC..990..250V |title=Continuum driven winds from super-Eddington stars. A tale of two limits |author= van Marle A.J; Owocki S.P. & Shaviv N.J. 2008 |journal=AIP Conference Proceedings |year=2008 |volume=990 |pages=250–253 |doi=10.1063/1.2905555|arxiv = 0708.4207 |s2cid=118364586 }}</ref> The Eddington limit explains the observed luminosity of accreting [[black holes]] such as [[quasars]]. == Super-Eddington luminosities == Eddington limit explains the very high mass loss rates seen in the outbursts of [[Eta Carinae|η Carinae]] in 1840–1860.<ref>{{cite journal |bibcode=2006ApJ...645L..45S |title=On the role of continuum driven eruptions in the evolution of very massive stars and population III stars |author=Smith N. & Owocki S.P. 2006 |journal=Astrophysical Journal |year=2006 |volume=645 |issue=1 |pages=L45–L48 |doi=10.1086/506523|arxiv = astro-ph/0606174 |s2cid=15424181 }}</ref> The regular stellar winds can only stand for a mass loss rate of about 10<sup>−4</sup>–10<sup>−3</sup> solar masses per year. Mass loss rates of up to 0.5 solar masses per year are needed to understand the η Carinae outbursts. This can be done with the help of the super-Eddington broad spectr