Take a look at Wikipedia section about photometry and spectroscopy. It seems that magnetite (so iron and oxygen) is present. https://en.wikipedia.org/wiki/1019

Take a look at Wikipedia section about photometry and spectroscopy. It seems that magnetite (so iron and oxygen) is present. https://en.wikipedia.org/wiki/101955_Bennu https://en.wikipedia.org/wiki/101955_Bennu