 A star 's life begins with the gravitational collapse of a gaseous nebula of material composed primarily of hydrogen , along with helium and trace amounts of heavier elements . When the stellar core is sufficiently dense , hydrogen becomes steadily converted into helium through nuclear fusion , releasing energy in the process . The remainder of the star 's interior carries energy away from the core through a combination of radiative and convective heat transfer processes . The star 's internal pressure prevents it from collapsing further under its own gravity . When the hydrogen fuel at the core is exhausted , a star of mass 0 @.@ 4 times greater than the Sun 's will expand to become a red giant . In some cases , it will fuse heavier elements at the core or in shells around the core . As the star expands it throws a part of its mass , enriched with those heavier elements , into the interstellar environment , to be recycled later as new stars . Meanwhile , the core becomes a stellar remnant : a white dwarf , a neutron star , or if it is sufficiently massive a black hole . 
 A star <a href='null_genetive' title='1'><mark>'s</mark></a>life <a href='uninflect' title='2'><mark>begins</mark></a> with the gravitational collapse of a gaseous nebula of material composed primarily of hydrogen , along with helium and trace amounts of heavier elements . When the stellar core <a href='drop_aux' title='3'><mark>is</mark></a>sufficiently dense , hydrogen <a href='uninflect' title='4'><mark>becomes</mark></a> steadily converted into helium through nuclear fusion , releasing energy in the process . The remainder of the star <a href='null_genetive' title='5'><mark>'s</mark></a>interior <a href='uninflect' title='6'><mark>carries</mark></a> energy away from the core through a combination of radiative and convective heat transfer processes . The star <a href='null_genetive' title='7'><mark>'s</mark></a>internal pressure <a href='uninflect' title='8'><mark>prevents</mark></a> it from collapsing further under its own gravity . When the hydrogen fuel at the core is exhausted , a star of mass 0 @.@ 4 times greater than the Sun <a href='null_genetive' title='9'><mark>'s</mark></a>will expand to become a red giant . In some cases , it will fuse heavier elements at the core or in shells around the core . As the star <a href='uninflect' title='10'><mark>expands</mark></a> it <a href='uninflect' title='11'><mark>throws</mark></a> a part of its mass , enriched with those heavier elements , into the interstellar environment , to be recycled later as new stars . Meanwhile , the core <a href='uninflect' title='12'><mark>becomes</mark></a> a stellar remnant : a white dwarf , a neutron star , or if it <a href='drop_aux' title='13'><mark>is</mark></a>sufficiently massive a black hole . 
A star  life begin w the gravitational collapse of a gaseous nebula of material composed primarily of hydrogen , along witw/lium and trace amounts of heavier elements . When da stellar core sufficiently dense , hydrogen become steadily converted into helium thru nuclear fusion , releasing energy in the process . The remainder of tdastar  interior carry energy away from the core through a combination of radiative and convective heat transfer processes . The star  internal pressure prevent it from collapsing further under its own gravity . When thdaydrogen fuel at thedare is exhausted , a star of mass 0 @.@ 4 times greater than the da  gon expand to become a red bigass . In some cases , it will fuse heavier elements at the core or in shells around the core . As the star expand it throw a part of its mass , enriched with witte heavier elements , into the interstellar environment , to be recycled later as new stars . Meanwhile , the core become a stellar remnant : a white dwarf , a neutron star , or if it sufficiently massive a black hole .