Evidence item

Here we show experimentally how oceans of water can be produced within the high-temperature H2-rich atmosphere above a terrestrial planet growing by capture of millimetre-to-centimetre-size silicate pebbles. We simulate this process by melting anhydrous mafic lithologies in H2 streams. Measurements show large amounts of water generated by hydrogen reduction of iron oxide to iron metal within several hours. We also find that the produced metal strongly sequesters phosphorus, stripping it from the silicate.