SOLAR SYSTEM

Detailed explanation-1: -The material in a white dwarf no longer undergoes fusion reactions, so the star has no source of energy. As a result, it cannot support itself by the heat generated by fusion against gravitational collapse, but is supported only by electron degeneracy pressure, causing it to be extremely dense.

Detailed explanation-2: -The core is stabilized and the end is near. The star will now begin to shed its outer layers as a diffuse cloud called a planetary nebula. Eventually, only about 20% of the star’s initial mass remains and the star spends the rest of its days cooling and shrinking until it is only a few thousand miles in diameter.

Detailed explanation-3: -A white dwarf is what stars like the Sun become after they have exhausted their nuclear fuel. Near the end of its nuclear burning stage, this type of star expels most of its outer material, creating a planetary nebula. Only the hot core of the star remains.

Detailed explanation-4: -For a star roughly 1 solar mass or less, the core never reaches the ignition temperature of carbon burning. The core cannot contract and heat up to a temperature needed to initiate carbon fusion. In about 75, 000 years it forms a white dwarf star, composed mostly of carbon.

Detailed explanation-5: -The vast majority of white dwarfs are formed after a dying star has shed its outer layers to form a planetary nebula, leaving behind an approximately Earth-sized inner core that is the white dwarf. Other white dwarfs in binary systems may explode as novae but then not go on to form a neutron star or a black hole.