06-03-2014, 07:06 PM
(This post was last modified: 06-03-2014, 07:07 PM by stevebowers.)
Let's see. Assume it has a radius of 2.31 Earths, (the lower bound) and a mass of 19 Earths, (the upper bound), then it has a surface gravity of 3,58 gees and an escape velocity of 32.1km/s.
The atmosphere on a planet like that would retain hydrogen, even at the planet's likely average temperature of 485K. Looking at the density, at 8.5g/cm3 this is more dense than Earth, but actually less dense than a ball of Earth-like material at that mass (compression would raise the density of such a ball to 9.1g/cm3). So this planet is made of material less dense than Earth's composition.
What does this mean? I think it means it has a moderately thick atmosphere and probably a layer of hot or supercritical water; a hot-water world, in fact. Alternately it might have no metallic core and be predominately silicates, with a hot dry atmosphere - but this seems less likely. Any other options? A massive carbon world?
The atmosphere on a planet like that would retain hydrogen, even at the planet's likely average temperature of 485K. Looking at the density, at 8.5g/cm3 this is more dense than Earth, but actually less dense than a ball of Earth-like material at that mass (compression would raise the density of such a ball to 9.1g/cm3). So this planet is made of material less dense than Earth's composition.
What does this mean? I think it means it has a moderately thick atmosphere and probably a layer of hot or supercritical water; a hot-water world, in fact. Alternately it might have no metallic core and be predominately silicates, with a hot dry atmosphere - but this seems less likely. Any other options? A massive carbon world?