Both early protostars and young stars are formed from a clod of gas which collapses under gravity to form a star. Both types of star are mainly Hydrogen and some Helium. They would be 75% Hydrogen, 25% Helium with traces of Lithium. Young stars formed out of the remains of old stars would still be mainly Hydrogen. Another way to say it is Both types of star are mainly Hydrogen and some Helium. Early protostars would have been formed from the gasses that were created soon after the big bang. They would be 75% Hydrogen, 25% Helium with traces of Lithium. Young stars formed out of the remains of old stars would still be mainly Hydrogen.
