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PostPosted: Mon Oct 22, 2012 4:35 am 
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Have another couple of systems - I posted the first one in the Obsessive Compulsive Die Based System Generation thread

Code:
   Num Star      Age    ZMass   Mass        ZLum             Lum         Rad   Met Pha
   142 G0 V     4.787   1.059   1.059      0.9674163      1.4686204     1.136   2   1
 
ZAMS Inner Zone =    0.808   Current Inner Zone =    0.986
ZAMS Earth Equiv=    0.984   Current Earth Equiv=    1.212
ZAMS Hab Zone   =    1.618   Current Hab Zone   =    1.977
ZAMS Outer Zone =    2.494   Current Outer Zone =    3.073
 
Num    AU        ecc       type      mass     den        rad        peri       aph      hill     inner     outer      4:1       3:2     migrate
 1     0.095     0.010     3.000     8.519  7739.600 79313.000     0.094     0.096     0.013     0.055     0.135     0.038     0.072     0.013
 2     0.171     0.083     1.000     0.207  1568.340 39080.000     0.157     0.185     0.007     0.136     0.219     0.068     0.130     0.013
 3     0.376     0.001     1.000     0.081  1543.440 28732.000     0.376     0.376     0.011     0.343     0.409     0.149     0.287     0.013
 4     0.639     0.061     1.000     0.124  1463.820 33768.000     0.600     0.678     0.021     0.536     0.785     0.254     0.488     0.013
 5     1.568     0.011     4.000     0.004  5000.000  7000.000     1.551     1.585     0.016     1.502     1.634     0.622     1.197     0.013
 6     2.352     0.143     4.000     0.002  3500.000  6000.000     2.015     2.689     0.019     1.968     2.801     0.933     1.795     0.013
Orbit = 1.568 AU, Radius =  7000. km, Density = 5000. kg/m3, Mass= .004 MJ, BBTemp=  245.0 K, MMW=     4.45, Atm=   9
Orbit = 2.352 AU, Radius =  6000. km, Density = 3500. kg/m3, Mass= .002 MJ, BBTemp=  200.0 K, MMW=     7.06, Atm=  10


That's a 'strongly migrated' system, which has no less than four gas giants inside the orbits of the terrestrial planets! The innermost planet is a massive Hot Jupiter with 8.5 jupiter masses, zooming around its primary with a period of only 10.4 days! The next three planets are "Hot Neptunes". Then there are two rocky planets that formed from the mess left behind after the jovians ploughed through the rocky protoplanetary disc.

The fifth planet is at roughly the same distance as Mars from Sol, but is slightly bigger than Earth (with the same density. It's a rocky/metallic world) - it has a habitable (tainted) atmosphere, but is somewhat colder. That said, once you take the density and albedo into account (not shown here) it's not too bad - the mean average temperature goes up to -4°C, which is still considerably colder than Earth but not terribly cold. Essentially, it's a glacial, ice-capped world but its equatorial regions may still get above freezing. It's the best chance for habitability in the system anyway.

Finally the sixth planet is a cold mars-like world, but it's the size of earth. The density is lower, so it may either be made of lower density rocky material, or might have a higher volatile component (possible, because of the mixing caused by the migrating jovians) so it might actually be a larger version of Europa - a water-rich world with a deep ocean layer covered by an icy shell.

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PostPosted: Mon Oct 22, 2012 4:56 am 
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Here's another one, this is a habitable system around an M0 V star.

Code:
Num:   67014
Star:      M0 V 
Age:       4.210
Zmass:     0.452
Mass:      0.452
ZLum:      0.0316244
Lum:       0.0323218
Rad:       0.408
Metal:     2
Phase:     1
 
ZAMS Inner Zone =    0.170   Current Inner Zone =    0.172
ZAMS Hab Zone   =    0.339   Current Hab Zone   =    0.343
ZAMS Earth Equiv=    0.178   Current Earth Equiv=    0.180
ZAMS Outer Zone =    0.451   Current Outer Zone =    0.456
 
Num    AU        ecc       type      mass     den        rad        peri       aph      hill     inner     outer      4:1       3:2     migrate
 1     0.050     0.017     4.000     0.006  5000.000  8000.000     0.049     0.051     0.001     0.047     0.054     0.020     0.038     0.425
 2     0.110     0.032     4.000     0.014  6500.000 10000.000     0.106     0.114     0.002     0.099     0.123     0.044     0.084     0.425
 3     0.187     0.074     4.000     0.002  5000.000  6000.000     0.173     0.201     0.002     0.167     0.212     0.074     0.143     0.425
 4     0.393     0.092     4.000     0.015  5000.000 11000.000     0.357     0.429     0.009     0.331     0.472     0.156     0.300     0.425
 5     1.030     0.401     1.000     0.041  1365.780 23802.000     0.616     1.443     0.031     0.538     1.695     0.409     0.786     0.425
 6     3.151     0.361     1.000     0.157  1530.900 35918.000     2.014     4.288     0.151     1.636     5.496     1.250     2.404     0.425
Orbit = 0.050 AU, Radius =  8000. km, Density = 5000. kg/m3, Mass= .006 MJ, BBTemp=  528.4 K, MMW=     7.34, Atm=  10
Orbit = 0.110 AU, Radius = 10000. km, Density = 6500. kg/m3, Mass= .014 MJ, BBTemp=  356.2 K, MMW=     2.44, Atm=  16
Orbit = 0.187 AU, Radius =  6000. km, Density = 5000. kg/m3, Mass= .002 MJ, BBTemp=  273.2 K, MMW=     6.75, Atm=   8 *
Orbit = 0.393 AU, Radius = 11000. km, Density = 5000. kg/m3, Mass= .015 MJ, BBTemp=  188.5 K, MMW=     1.39, Atm=  17


This is a stable system around a red dwarf star that is just under half the mass of Sol, containing four rockies and two small 'cold neptune' jovians. It's somewhat more compact than the Solar System (it would only extend out to our own asteroid belt). Most of the rockies are quite large - the one in the habitable zone is a tidelocked planet that is otherwise similar to Earth (with a denser breathable atmosphere), but the other three rockies are superearths. The outermost superearth is actually a small "subgiant" weighing in at 4.7 earth masses - it has a dense hydrogen/helium atmosphere over a deep supercritical ocean, and is itself about half the size of the 'cold neptune' in the next orbit. The two 'neptunes' are in somewhat eccentric orbits, caused by interactions with a third small jovian between them that was subsequently ejected from the system.

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PostPosted: Tue Oct 23, 2012 2:13 am 
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Tell me more about supercritical oceans.

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PostPosted: Tue Oct 23, 2012 3:55 am 
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Agemegos wrote:
Tell me more about supercritical oceans.


If you put water under enough pressure (and above a certain temperature) it becomes supercritical, which essentially means it's a "fluid" with properties of both a liquid and a gas. I've never entirely grokked what that means, but I imagine it as if you're going down deeper into the atmosphere, and the 'air' gets thicker and thicker, and it grades into this more liquid-like stuff, and you keep going and then you get to a true liquid phase. So there's no real boundary between the 'sky' and the 'sea'. At least, that's how I picture it.

http://en.wikipedia.org/wiki/Supercritical_fluid explains it nicely.

http://www.lsbu.ac.uk/water/phase.html has a good phase diagram of water - the red dot in the first diagram there is the critical point. So to the right of that, the water is supercritical. (which in planetary terms corresponds to a pressure of > 220 atms and temperature over about 650K. Hm... I'm not entirely sure if the temperature would get that high at the base of the atmosphere on a 'cold' subgiant like the one I showed - it's certainly possible on one in the inner system or habitable zone though)

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PostPosted: Tue Oct 23, 2012 5:05 am 
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Hmm. Supercritical fluids turn into liquids without a phase change if you cool them, and into gases without a phase change if you reduce their pressure. Which I think means that supercritical oceans must have no upper surface. They grade continuously into the gas above them. There can be no such thing as evaporation from such an ocean, and I'm a bit unclear on whether there is any sensible difference between such an ocean and an atmosphere. A normal atmosphere would condense if you cooled it, but then a normal ocean would boil if you reduced its pressure, and this won't do either.

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PostPosted: Tue Oct 23, 2012 5:11 am 
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Agemegos wrote:
Hmm. Supercritical fluids turn into liquids without a phase change if you cool them, and into gases without a phase change if you reduce their pressure. Which I think means that supercritical oceans must have no upper surface. They grade continuously into the gas above them. There can be no such thing as evaporation from such an ocean, and I'm a bit unclear on whether there is any sensible difference between such an ocean and an atmosphere. A normal atmosphere would condense if you cooled it, but then a normal ocean would boil if you reduced its pressure, and this won't do either.


Yeah, that's basically how I understood it. Though I guess if you reduce the pressure and cooled it to below the critical point then it would at least separate out into liquid and gas phases again... which is kinda like condensing and boiling at the same time ;).

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PostPosted: Tue Oct 23, 2012 5:33 am 
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The atmosphere of Venus is a supercritical fluid at the surface, and the atmospheres of Jupiter and Saturn are supercritical fluids below certain depths. It is interesting that materials can dissolve in a supercritical fluid but not in the gas above it. I suppose that you might get a stable boundary like the halocline, with a discontinuity of density at the critical pressure because the supercritical fluid below is laden with solutes not present in the gas above. Sort of like those hypersaline underwater lakes and streams.

Presumably solutes sublime out and fall like rain or snow when the parcel of fluid they are in is transported above the altitude corresponding to critical temperature. Or do they form a fog of suspended particles? Solutes give up latent heat of crystallisation when they precipitate, I think. So a parcel of supercritical fluid lifted above the critical pressure will suddenly become warmer and less dense as its dissolved solids and liquids rain out. Interesting weather on the halopressurecline!

Does this mean that the atmosphere of Venus is filled with fog and haze where it is gaseous, but is much more transparent in the lower layers where it is supercritical?

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PostPosted: Fri Jun 27, 2014 4:38 pm 
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So with all of the hot Jovians and Super-Mega-Earths being discovered,
have you given any thought to tweaking a few parameters for the EDG Ultra-realistic systems?

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PostPosted: Sat Jun 28, 2014 3:14 am 
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atpollard wrote:
So with all of the hot Jovians and Super-Mega-Earths being discovered,
have you given any thought to tweaking a few parameters for the EDG Ultra-realistic systems?


Maybe you should take a look at the two systems I posted almost two years ago (wow) at the top of this page again ;) - the first one has hot jovians very close to the star and the second one has superearths.

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PostPosted: Wed Aug 20, 2014 2:13 am 
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Q about world placement, etc.

In this system, do you generate the gas giants first? I would imagine that they'd have some effect on the development of rocky worlds.

Also, what's the likelihood of a system forming without any gas giants?


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