 The star with the lowest iron content ever measured is the dwarf <unk> @-@ <unk> , with only 1 / <unk> the iron content of the Sun . By contrast , the super @-@ metal @-@ rich star <unk> <unk> has nearly double the abundance of iron as the Sun , while the planet @-@ bearing star 14 <unk> has nearly triple the iron . There also exist chemically peculiar stars that show unusual <unk> of certain elements in their spectrum ; especially <unk> and rare earth elements . Stars with cooler outer atmospheres , including the Sun , can form various <unk> and <unk> molecules . 
