 Unlike the lower mass noble gases , the normal stellar nucleosynthesis process inside a star does not form xenon . Elements more massive than iron @-@ 56 have a net energy cost to produce through fusion , so there is no energy gain for a star when creating xenon . Instead , xenon is formed during supernova explosions , by the slow neutron capture process ( s @-@ process ) of red giant stars that have exhausted the hydrogen at their cores and entered the asymptotic giant branch , in classical nova explosions and from the radioactive decay of elements such as iodine , uranium and plutonium . 
 Unlike the lower mass noble gases , the normal stellar nucleosynthesis process inside a star <a href='uninflect' title='1'><mark>does</mark></a> not form <a href='negative_concord' title='2'><mark>xenon</mark></a> . Elements more massive than iron @-@ 56 <a href='got' title='3'><mark>have</mark></a> a net energy cost to produce through fusion , so <a href='dey_it' title='4'><mark>there</mark></a> is no energy gain for a star when creating xenon . Instead , xenon is formed during supernova explosions , by the slow neutron capture process ( s @-@ process ) of red giant stars <a href='null_relcl' title='5'><mark>that</mark></a><a href='been_done' title='6'><mark>have</mark></a> exhausted the hydrogen at their cores and entered the asymptotic giant branch , in classical nova explosions and from the radioactive decay of elements such as iodine , uranium and plutonium . 
Unlike da lower mass noble gases , tdanormal stellar nucleosynthesis process inside a star do not form no xenon . Elements more massive den iron @-@ 56 got a net energy cost to produce through fusion , so it ain't no energy gain for a star when creating xenon . Instead , xenon is formed durin supernova explosions , by the slow neutron capture process ( s @-@ process ) of red bigass stars done exhausted the hydrogen at their cores and entered thdasymptoticbigasst branch , in classical nova explosions and from the radioactive decay of elements such as iodine , uranium and plutonium .