Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

I Solar system simulation -- Significant deviation of some Jovian moons

  1. Jul 21, 2017 #1
    I am working on a simulation of the solar system, but I am having problems with the orbits with Europa and Io shown in the image below, the orbits of Jupiter, Ganymede and Callisto are consistent with NASA's simulations. For all bodies I have used identical parameters in generating the initial values (position and velocities) from NASA Horizons, but the simulated velocities deviate significantly from the reference values, see below the image.


    jupiter_moons.png

    Code (Text):
    Simulated velocities Io
    [[ -8614.49286 -21369.57154   -632.93203]
    [  9413.68985 -45300.37648  -1230.23422]
    [  9386.14932 -44351.41911  -1197.69465]
    [  9380.29852 -44091.59352  -1189.38208]
    [  9384.20206 -43964.90674  -1185.66855]
    [  9392.3708  -43887.48053  -1183.64575]
    [  9402.739   -43833.83182  -1182.43573]
    [  9414.37123 -43793.50441  -1181.67948]
    [  9426.78351 -43761.39524  -1181.20215]
    [  9439.70035 -43734.71132  -1180.90818]]
    Reference velocities Io
    [[ -8.6145e+03  -2.1370e+04  -6.3293e+02]
    [  1.4312e+04   3.7050e+03   5.8373e+02]
    [  3.2327e+03  -2.8330e+04  -7.1454e+02]
    [  5.2868e+02   5.4834e+03   4.5001e+02]
    [  1.6449e+04  -2.4527e+04  -3.9360e+02]
    [ -1.0069e+04  -3.4329e+03  -1.9295e+01]
    [  2.2782e+04  -1.2263e+04   1.3100e+02]
    [ -1.0724e+04  -1.7200e+04  -5.2041e+02]
    [  1.8110e+04   7.9950e+02   5.2812e+02]
    [ -1.1648e+03  -2.7069e+04  -7.3810e+02]]
    Simulated velocities Europa
    [[ 17409.7477 -17977.8844   -149.1204]
    [ 19892.0848  -6577.1288    388.6789]
    [ 15345.577   -6005.3129    330.4903]
    [ 13644.4897  -6241.7316    288.5844]
    [ 12703.5633  -6475.9464    260.4778]
    [ 12088.5888  -6670.4873    239.9645]
    [ 11648.2814  -6830.9437    224.0745]
    [ 11314.4114  -6965.0308    211.2436]
    [ 11051.081   -7078.774     200.5634]
    [ 10837.3529  -7176.5748    191.4658]]
    Reference velocities Europa
    [[ 17409.7477 -17977.8844   -149.1204]
    [  9657.1567   1697.3447    562.7489]
    [ -8209.8182  -9418.8943   -242.2855]
    [  6511.8877 -25017.7237   -653.561 ]
    [ 18583.2     -7391.2116    327.0779]
    [  -703.984     970.8296    340.24  ]
    [ -5401.237  -19722.1106   -642.0661]
    [ 16113.2379 -19990.1371   -266.1455]
    [ 12018.9873    776.3151    558.5457]
    [ -7545.2962  -6950.3879   -130.6148]]
    These are the first ten velocities in vx, vy, vz-format. The stepsize used is 24 hours.

    The physical constants, using in the simulation are
    Code (Text):
    NAME,RADIUS,GM, COMMENT,
    Sun, 695700e3,1.3271244004193938e20, "Source: NASA/JPL Horizons",
    Mercury, 2439.7e3,22032.09e9, "Source: NASA/JPL Horizons",
    Venus, 6051.8e3,324858.63e9, "Source: NASA/JPL Horizons",
    Earth, 6371.0e3,398600.440e9, "Source: NASA/JPL Horizons",
    Mars, 3389.5e3,42828.3e9, "Source: NASA/JPL Horizons",
    Jupiter, 69911e3,126686511e9, "Source: NASA/JPL Horizons",
    Saturn, 58232e3,37931207.8e9, "Source: NASA/JPL Horizons",
    Uranus, 25362e3,5793966e9, "Source: NASA/JPL Horizons",
    Neptune, 24622e3,6835107e9, "Source: NASA/JPL Horizons",
    Pluto, 1737.4e3,872.4e9, "Source: NASA/JPL Horizons",
    Luna, 469.7e3, 4902.801076e9, "Source: JPL, Lunar Constants and Models Document",
    Ceres, 469.7e3,62.6284e9, "Source: NASA/JPL Horizons",
    Pallas, 272.5e3,14.3e9, "Source: NASA/JPL Horizons",
    Vesta, 262.7e3,17.8e9, "Source: NASA/JPL Horizons",
    Hygiea, 203.56e3,7e9, "Asteroid. Source: NASA/JPL Horizons",
    Ganymede, 2634e3,9887.83e9, "Moon of Jupiter. Source: International Astronomical Union, Icy Bodies of the Solar System",
    Titan, 2575.5e3,8978.1356e9, "Moon of Saturn. Source: International Astronomical Union, Icy Bodies of the Solar System",
    Callisto, 2410.3e3,7179.29e9, "Moon of Jupiter. Source: International Astronomical Union, Icy Bodies of the Solar System",
    Io, 1821.46e3,5959.916e9, "Moon of Jupiter. Source: International Astronomical Union, Icy Bodies of the Solar System",
    Europa, 1562.09e3,3202.72e9, "Moon of Jupiter. Source: International Astronomical Union, Icy Bodies of the Solar System",
    Any help would be appreciated :)

    .. Mads
     
  2. jcsd
  3. Jul 21, 2017 #2

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    Io has an orbital period of 1.7 days. With a step size of 1 day, you cannot get a realistic orbit.
    Europa has an orbital period of 3.6 days, still too low.
    Ganymede has 7 days and Callisto has 17 days, for these moons steps of 1 day can lead to something that looks like an orbit (with a large error, however),
     
  4. Jul 21, 2017 #3
    A smaller timestep fixed it, sorry for not looking before posting.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Solar system simulation -- Significant deviation of some Jovian moons
  1. A jovian moon? (Replies: 1)

Loading...