If the sun began as a rapidly growing and rapidly rotating 60 JM (Jupiter mass) brown dwarf then it was at that time almost entirely metallic hydrogen/helium surrounded by a thin (1300km) ocean of 1 EM (Earth mass) of liquid hydrogen/helium. (Saturn has about 8 EM of liquid hydrogen/helium and 87 EM of something else)
The pressure at the bottom of this liquid hydrogen/helium ocean would have been
1300km * (0.0794g/cm^3) * 60*2.528(9.8m/s^2) in bar = 1.5 million bar
Based on the abundace of the elements, 1.5% (0.9 JM) of the 60 JM protosun should have been carbon (95-13=82 EM, see below) and oxygen (190-25=165 EM) so it is possible that between the liquid hydrogen/helium ocean and the metallic hydrogen/helium there may have been a 3000km thick layer (if 8 g/cm^3) of metallic carbon and metallic oxygen
It might have been less than that if, for one reason or another, part of it (the oxygen) sank
If hydrogen only comes in two flavors, nondegenerate liquid hydrogen and degenerate metallic hydrogen, then it's very hard to see how a planet could keep the same radius as its mass increases from 1 to 60 JM. It is necessary therefore to suppose that metallic hydrogen comes in two forms, one much denser than the other. A partially degenerate metallic hydrogen and a fully degenerate metallic hydrogen.
The layers would have looked like this:
Nondegenerate liquid hydrogen and helium (0.0794 g/cm^3)
Nondegenerate metallic carbon and oxygen
Partially degenerate metallic hydrogen and helium (8 g/cm^3)
Partially degenerate metallic carbon and oxygen
Fully degenerate hydrogen (>80 g/cm^3)
Fully degenerate carbon and oxygen
When the pressure in the core of the 60 JM protosun became great enough and the fully degenerate metallic hydrogen core finally collapsed the protosun would have begun to spin faster due to conservation of angular momentum. If it spun fast enough then its outermost layers of liquid hydrogen and metallic oxygen and metallic carbon would have been thrown out into space where it would have coalesced into a moon which would have immediately begun receding from the rapidly rotating protosun due to tidal interactions.
One orbit would be completed in only 25 minutes.
2*pi*sqrt((76000 km)^3/(G*60*317 earth masses)) = 25 min
If it continued to spin faster and faster then eventually part of its metallic hydrogen (now the outermost layer) would have been thrown out into space and would have formed a second moon which would also have immediately begun receding due to tidal interactions. The metallic hydrogen must have been solid originally since it didnt end up in the 1st moon but the heat released by the core collapse evidently caused a vast flood of metallic hydrogen lava that covered the surface (cf flood basalt)
Maybe, just maybe, Saturn=1st moon and Jupiter=2nd moon (I'm just throwing it out there as a possibility)
This would explain why hot Jupiters are so common
Jupiter's orbital momentum is far larger than the suns rotational angular momentum.
The moons orbital momentum is 4 times the Earths rotational angular momentum.
Jupiter would have been 1/60th of the mass of the protosun.
The Moon is 1/80th of the mass of Earth.
outer 4000 km of the protosuns partially degenerate metallic hydrogen = 1 JM
60*10^9 km^2 * 4000 km * 8 g/cm^3 in Earth masses = 321.5 Earth masses
4000 km might be the depth at which the metallic hydrogen transitioned to a denser phase.
60*2.528(9.8m/s^2) * (saturn mass + Jupiter mass) / (Jupiter surface area) in bar = 600 million bar
60*2.528(9.8m/s^2) * (5.7*10^26kg + 1.9*10^27kg) / (61 * 10^9 km^2) in bar = 600 million bar
Uranus and Neptune would have been created earlier by a similar process when the pressure in the core of the 8 JM protosun reached 600 million bar and the partially degenerate metallic hydrogen core collaped creating fully degenerate metallic hydrogen. Still no explanation for the odd rotation of Uranus but a collision is far more likely near the sun than further out.
The pressure in the center of Jupiter is 150 million bar if its metallic hydrogen has a density of 8 g/cm^3
0.5*76000km * (8g/cm^3) * 2.528(9.8m/s^2) * 0.5 in bar
0.5*76000km = radius of core
By the time the protosun grew to 8 JM the core would be twice as big and the pressure in the center would be 4 times higher, 600 million bar
And its liquid hydrogen ocean would be 0.1*76550km deep (6.77 EM)
0.1 * 76550km * (0.0794g/cm^3) * 8 * 2.528(9.8m/s^2) in bar = 1.2 million bar = pressure at bottom of liquid hydrogen ocean
1.5% of the 8 JM protosun would be of metallic carbon (13 EM) and oxygen (25 EM)
As Jupiter receded, the Protosun's rotation would have temporarily slowed and gas and dust from the circumstance disc would once again have begun to accumulate on it. If the rotation increased again then a planet of rock and iron could have formed. 1 EM would form a layer 20km deep. At 150 g thats equivalent to 3000km at 1 g. Earth contains 0.25 EM of iron. 250 EM of gas would have to fall on to the protosun to bring that much iron. Since the rock and iron werent metallic that gas must somehow have been ejected from the rapidly rotating protosun.
Had Saturn and Jupiter continued to grow into Stars then one of them would have been ejected from the system (a 3-body system is unstable) and we would now be in a binary star system.
The planet that was not ejected would have grown until it also had 2 large moons; of which, at least one would have been ejected too.
In this way, each star system spawns 2 more star systems until the molecular cloud is destroyed by a supernova.
I always assumed that the circumstellar disk was destroyed when the sun began fusing hydrogen. But I guess it just dissipated naturally once the molecular cloud that was feeding it was destroyed by a supernova
https://en.wikipedia.org/wiki/Brown_dwarf
http://www.science20.com/robert_inve...65279;
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
