With similar masses, the atoms can hold similar amounts of heat just as similar sized cups can hold the same amount of boiling water. (principia-scientific.org)
It is unlikely that a mixture of the two processes would have produced planets with such similar masses, they say. (newscientist.com)
But if the abundances of heavy elements in atmospheres of exoplanets in other systems resemble the abundances for planets of similar mass closer to home, then those exoplanets were probably created in similar ways. (sciencenews.org)