Within 50 million years, the pressure and density of hydrogen in the centre of the protostar became great enough for it to begin thermonuclear fusion.
Veliki planeti (Jupiter, Saturn, Uran in neptun) so se oblikovali bolj daleč, onkraj meje zmrzovanja ("frost line" - točka med Marsom in Jupitrom kjer je material dovolj hladen, da hlapljive ledene sestavine ostanejo trdne).