Another Orbital data question
- Thread starter Drakon
- Start date
For M (in earth masses) the range will be from 10 (the smallest GG) to around 4,000. Any larger and you're getting into brown dwarf territory. Jupiter is around 317 earth masses. Saturn is around 95 earth masses. Neptune and Uranus are both around 15 earth masses.
As a general range 10-80 earth masses for small gas giants, 80-1000 for large gas giants.
As a general range 10-80 earth masses for small gas giants, 80-1000 for large gas giants.
Keeping in mind that current theories indiccate that, somewhere around 3200ME (10MJ) one hits a plateau in diameter... as the core begins to collapse it's electron shells, and density begins to climb. (Or so the recent papers claim.)
shaunhilburn
SOC-12
This is Kepler's third law for a circular orbit. P=sqrt(D³/M), M=D³/P², and D=cuberoot(MP²).
You can plug in the parameters of *any* circular reference orbit, like M = solar masses, D = 1 AU, P = 1 earth year = 365.256 days.
I'll use:
M = earth masses
D = 6378.1 km (Earth's equatorial radius)
P = 5068 sec = Schuler period (for a zero-altitude surface grazing orbit/Herget orbit)
A moon orbiting 62 earth radii from a 700 earth-mass GG:
P = SQRT ( 62³/700 ) x 5068 = 93514 seconds = 25.98 hours
Drakon
SOC-14 1K
Thank you for your replies. This gives me some numbers to play with.
The eventual product will be a spreadsheet that computes orbital period, and angular size of the gas giant in the sky, based on the gas giant size.
However, I do not have planetary masses for planets sized 11 through 24. I have diameters, but not masses. For sizes 10 and less I am using the info from CT B6. (Greater than 24, from T5 and Wikipedia)
For angular size, I find that some orbits could get interesting, where the gas giant's shadow would give the planet, at least in some parts, a double double day. One would get a brief period of daylight in the morning and another at night, as the satellite swung around its orbit. For a size T world, Orbit Eff would have a 10.10 hour orbit, but the gas giant takes up 127 degrees of sky, or eclipses the satellite for 3 &1/2 of the 5 hour daylight time.
The eventual product will be a spreadsheet that computes orbital period, and angular size of the gas giant in the sky, based on the gas giant size.
However, I do not have planetary masses for planets sized 11 through 24. I have diameters, but not masses. For sizes 10 and less I am using the info from CT B6. (Greater than 24, from T5 and Wikipedia)
For angular size, I find that some orbits could get interesting, where the gas giant's shadow would give the planet, at least in some parts, a double double day. One would get a brief period of daylight in the morning and another at night, as the satellite swung around its orbit. For a size T world, Orbit Eff would have a 10.10 hour orbit, but the gas giant takes up 127 degrees of sky, or eclipses the satellite for 3 &1/2 of the 5 hour daylight time.
The mass of a world with size 8 is 1 (assuming Earth mass). You should be able to calculate the mass of other worlds from that as S/8 cubed where S is the size of the world.
Hans
Drakon
SOC-14 1K
Thank you, that works. The mass progression looks reasonable up until size 21. Size 25 is defined as Saturn sized = 95 earth masses. By formula, size 25 is 30.5 earth masses. The scale goes non linear after Size 21.
I suspect you mean "(assuming Earth density)" since mass would be redundant.
Anything over about size 15 is going to have a Min Molecular Weight retained sufficient to turn into a gassball of much larger diameters.
Note that Saturn is around 72,000 miles diameter (apparent size 72), 95 earth masses. and a density of 0.7g/cc, versus earth's 5.5, for a density of 0.12 earths. The Mass derived size would be (95^(1/3))*8, or 36.
Note that T5 puts the change in scale for size at Size 20, and goes wonky at 29.
| UWP | Size | Diameter | Benchmark |
| 1 | 1 | 1,000 | (Ceres) |
| 2 | 2 | 2,000 | - |
| 3 | 3 | 3,000 | - |
| 4 | 4 | 4,000 | (Mars) |
| 5 | 5 | 5,000 | - |
| 6 | 6 | 6,000 | - |
| 7 | 7 | 7,000 | - |
| 8 | 8 | 8,000 | Earth |
| 9 | 9 | 9,000 | - |
| A | 10 | 10,000 | - |
| B | 11 | 11,000 | - |
| C | 12 | 12,000 | - |
| D | 13 | 13,000 | - |
| E | 14 | 14,000 | - |
| F | 15 | 15,000 | - |
| G | 16 | 16,000 | - |
| H | 17 | 17,000 | - |
| J | 18 | 18,000 | - |
| K | 19 | 19,000 | - |
| L | 20 | 20,000 | - |
| M | 21 | 30,000 | Neptune (Uranus) |
| N | 22 | 40,000 | - |
| P | 23 | 50,000 | - |
| Q | 24 | 60,000 | - |
| R | 25 | 70,000 | Saturn |
| S | 26 | 80,000 | - |
| T | 27 | 90,000 | Jupiter |
| U | 28 | 125,000 | 2MJ |
| V | 29 | 180,000 | 4MJ |
| W | 30 | 220,000 | 6MJ |
| X | 31 | 250,000 | 8MJ |
Last edited:
shaunhilburn
SOC-12
Try this
Code:
Mass, radius, density, gravity of silicate/nickel-iron planetary spheres,
core mass fraction = 32.5%
size radius mass density gravity X(m.r) X(m.g) mmwr atmos
-------------------------------------------------------------------------------
0.2 0.0253 0.0000 0.5088 0.013 0.3141 0.3718 0
0.3 0.0379 0.0000 0.5133 0.019 0.3121 0.3757 0
0.5 0.0632 0.0001 0.5224 0.033 0.3091 0.3818 0
1.0 0.1263 0.0011 0.5457 0.069 0.3037 0.3926 0
1.5 0.1895 0.0039 0.5702 0.108 0.2996 0.4008 0
2.0 0.2526 0.0096 0.5957 0.150 0.2962 0.4077 0
2.5 0.3158 0.0196 0.6223 0.197 0.2931 0.4137 159.6 1-, A+
3.0 0.3789 0.0354 0.6502 0.246 0.2904 0.4192 106.1 1-, A+
3.5 0.4421 0.0587 0.6793 0.300 0.2879 0.4243 74.6 1, A+
4.0 0.5052 0.0915 0.7097 0.359 0.2855 0.4289 54.7 1, A+
4.5 0.5684 0.1361 0.7414 0.421 0.2833 0.4334 41.3 1, A+
5.0 0.6315 0.1951 0.7746 0.489 0.2812 0.4375 32.0 2 - 5, A+
5.5 0.6947 0.2713 0.8093 0.562 0.2793 0.4415 25.4 2 - 5, A+
6.0 0.7578 0.3679 0.8455 0.641 0.2774 0.4453 20.4 2 - 5, A+
6.5 0.8210 0.4887 0.8833 0.725 0.2756 0.4489 16.6 2 - 7, A+
7.0 0.8841 0.6377 0.9228 0.816 0.2738 0.4524 13.7 2 - 9, A+
7.5 0.9473 0.8195 0.9641 0.913 0.2721 0.4557 11.4 2 - 9, A+
8.0 1.0104 1.0391 1.0072 1.018 0.2705 0.4590 9.6 4+
8.5 1.0736 1.3021 1.0523 1.130 0.2689 0.4621 8.2 4+
9.0 1.1367 1.6148 1.0994 1.250 0.2674 0.4652 7.0 6+
9.5 1.1999 1.9842 1.1486 1.378 0.2659 0.4681 6.0 6+
A 10.0 1.2630 2.4178 1.2000 1.516 0.2645 0.4710 5.2 8+
10.5 1.3262 2.9241 1.2537 1.663 0.2631 0.4738 4.5 8+
B 11.0 1.3893 3.5125 1.3098 1.820 0.2617 0.4765 3.9 8+
11.5 1.4525 4.1931 1.3684 1.988 0.2604 0.4792 3.4 8+
C 12.0 1.5156 4.9774 1.4296 2.167 0.2591 0.4818 3.0 8+
12.5 1.5788 5.8775 1.4936 2.358 0.2578 0.4843 2.7 8+
D 13.0 1.6419 6.9073 1.5604 2.562 0.2566 0.4868 2.4 B+
13.5 1.7051 8.0814 1.6302 2.780 0.2554 0.4893 2.1 B+ <-- gas giant core
E 14.0 1.7682 9.4163 1.7032 3.012 0.2542 0.4916 1.9 B+ evaporated gas giants
14.5 1.8314 10.9298 1.7794 3.259 0.2530 0.4940 1.7 B+
F 15.0 1.8945 12.6413 1.8590 3.522 0.2519 0.4963 1.5 B+
15.5 1.9577 14.5722 1.9422 3.802 0.2507 0.4985 1.3 B+
16.0 2.0208 16.7455 2.0291 4.100 0.2496 0.5007 1.2 B+Drakon
SOC-14 1K
I have posted my mass values, from Book 6 wikipedia and rancke's formula. Mass values are in earth mass = 1 units.
Note gap for 22, 23, 24.
