Planetary nebula

Planetary nebula

   Planetary nebula - celestial object consisting of ionized gas shell and the central star, white dwarf.

   Planetary nebulae are formed when resetting external layers (shells) of red giant and supergiant with a mass of solar 2,5-8 in the final stages of their evolution. Planetary nebula - fast (by astronomical standards) is that last only a few tens of thousands of years, with life-star ancestor several billion years. At present in our galaxy is known about 1500 planetary nebulae.

   The process of education of planetary nebulae, along with flashes of supernovae, plays an important role in the chemical evolution of galaxies, throwing in the interstellar space of the material enriched in heavy elements - the products of stellar nucleosynthesis (in astronomy are all heavy elements, with the exception of the primary products of the Big Bang nucleosynthesis - the hydrogen and helium such as carbon, nitrogen, oxygen and calcium).

   In recent years, with the help of images from space telescope "Hubble" we found out that many planetary nebulae are very complex and peculiar structure. Despite the fact that approximately one fifth of them had okolosfericheskuyu form, the majority did not have any kind of spherical symmetry. The mechanisms through which education might such diversity of forms, remain to date has not been clarified. It is believed that a major role in this interaction could play a stellar wind, and binary stars, the magnetic field and the interstellar medium.