планетарная туманность(A white dwarf is the evolutionary endpoint of a sun-like star. After such a star swells to become a red giant, then runs out of the fuel required for nuclear fusion reactions, the star ejects its outer layers to form a planetary nebula, or a shell of diffuse gas. As the nebula expands and dissipates, it leaves behind the star's inert core, which is what we call a white dwarf.)