Labels:text | flower | screenshot OCR: DYING STARS A STAR ENTERS its dying phase when nuclear reactions in its core finally cease, causing the star's structure to become unstable. A star of relatively low mass "burns" its nuclear fuel slowly over billions of years then evolves into a red giant. It then disintegrates to form a planetary nebula (an expanding shell of gas) surrounding a white dwarf. A star of high mass uses up its fuel more quickly, over only millions of years, and then evolves into a supergiant. It then erupts in a huge explosion called a THE CAT'S-EYE NEBULA, A PLANETARY NEBULA Whatever the mass of a dying star, much of its supernova. The remaining core forms material is thrown off into space to be recycled into a neutron star or a black hole. new generations of stars. SEE WHITE SUPERNOVAS NEUTRON STARS BLACK NE ...
