Zlender Images
S P E C T R A
M57 - Ring Nebula
| More than 1100 planetary nebula were found in our own galaxy. They are formed in a late evolutionary stage of a low mass star, which is visible at the center of the image on the right side. Temperatures of these very hot stars range from 30000K - 150000K so they are the source of ionizing, ultraviolet radiation for the nebulae. The spectrum below reveals that planetary nebulae are emission line objects. A cascade of photons in the IR, Optical and UVare emitted when an electron recombines with an ion. Back in 1927 I.S.Bowens detected that the strong lines at 4958.9A and 5006.8A are forbidden lines in the OIII spectrum and are not indicators of the mysterious element "Nebulium" as they were interpreted until that date. |
M57 - Ring Nebula
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