translate English to French: Two of these newlydiscovered planets would appear to be bodies of rock with a mass close to that of Neptune (17 times that of Earth) and thus much less dense than Jupiter (which ‘weighs’ 318 times more than Earth).
De ces trois nouvelles trouvailles, deux seraient rocheuses, dotées de masses proches de celles de Neptune (17 fois celle de la Terre), donc bien plus faibles que Jupiter (qui «pèse» 318 fois la Terre).