[[Imaxe:M57 The Ring Nebula.JPG|thumb|Unha nebulosa planetaria, aqui representada pola [[Nebulosa do Anel]], é un exemplo de nebulosa de emisión.]]
AnUnha '''emissionnebulosa nebulade emisión''' ise aunha [[cloud]]nube of [[ionized]]de [[gas ionizado]] (''i.eex.'' ao [[Plasma (physicsfísica)|plasma]]) emittingque lightemite ofluz variousen colorsvarias cores. TheA mostfonte commonmáis sourcecomún forde [[ionizationionización]] areson high-energyos [[photonfotón]]s emittedde fromalta a[[enerxía]] nearbyemitidos hotpor unha [[starestrela]] activa próxima. Among the several different types of emission nebula are [[H II region]]s, in which star formation is taking place and young, massive stars are the source of the ionising photons; and [[planetary nebula]]e, in which a dying star has thrown off its outer layers, with the exposed hot core then ionizing them.
