Is there an upper limit to the density of a planet's core?
Well, I believe Jupiter has a core of hydrogen, but apparently its state is not known.For instance, might the upper limit for the density of planet cores in general be the limiting density of solid hydrogen, or even that of neutronium?
http://www.astrophysicsspectator.com/topics/degeneracy/BrownDwarf.htmlHydrogen provides the first source of thermonuclear power to stars. The most massive stars, those over 100 times the Sun's mass, blast through this fuel in 1 million years or less. The Sun, with its dramatically lower rate of power generation, takes about 9 billion years to burn through its smaller reservoir of hydrogen. This trend of slower power generation by smaller stars continues down to the common 1/4 solar mass stars, which are expected to burn their fuel in about 100 billion years. Below 0.072 solar masses, the thermonuclear fusion of hydrogen becomes impossible. The objects immediately below this critical mass are called brown dwarfs.
More precisely, a brown dwarf is a massive ball of hydrogen, helium, and trace amounts of metals that is not massive enough to burn hydrogen, but is massive enough to burn deuterium. Brown dwarfs are expected to have masses ranging from just below 0.072 solar masses (78 times Jupiter's mass), the mass below which hydrogen fusion becomes impossible, down to 0.012 solar masses (13 time Jupiter's mass), the mass below which deuterium fusion becomes impossible. Anything smaller than 0.012 solar masses is a giant gaseous planet. From its spectrum, the brown dwarf appears to be simply an exceedingly cool star, but a brown-dwarf's inability to burn hydrogen betrays a fundamental physical difference between it and a star: unlike a star, a brown dwarf does not need thermonuclear fusion to hold itself up.
No. But the material has to be under sufficient pressure to be confined against electrostatic forces trying to return it to normal density.Is there an upper limit to the density of a planet's core?