A low or medium mass star (with mass less than about 8 times the mass of our Sun) will become a white dwarf. A typical white dwarf is about as massive as the Sun, yet only slightly bigger than the Earth.
Smaller stars, however, will take a slightly more sedate path. Low- to medium-mass stars, such as the sun, will eventually swell up into red giants. After that, the stars shed their outer layers into a ring known as a planetary nebula (early observers thought the nebulas resembled planets such as Neptune and Uranus). The core that is left behind will be a white dwarf, a husk of a star in which no hydrogen fusion occurs.
Smaller stars, such as red dwarfs, don’t make it to the red giant state. They simply burn through all of their hydrogen, ending the process as a dim white dwarf. However, red dwarfs take trillions of years to consume their fuel, far longer than the 13.8-billion-year-old age of the universe, so no red dwarfs have yet become white dwarfs.
Credit : Space.com
Picture Credit : Google
