Systemic Project - Simulations
The Systemic project is seeking
to improve our understanding of extra-solar planetary systems and is
described in detail on their website at
systemic.
This page has been set up to provide animated views of extra-solar planetary systems (real or simulated)
that have been defined using the Systemic Console.
(see here
for a high speed integrator for your systemic console)
Mandatory fields:
- The File selected above must be in the format of a 'fit' file saved by the Systemic console.
- The Mass should be that of the central star in solar masses.
This is found from the star's data file in the Systemic Console.
(Unfortunately this cannot be obtained from the fit file).
- Press the GO button to start the simulation.
Options:
- Inclination: The Inclination is the inclination of the plane of the planets' orbits
relative to the plane of the sky. (Quote from Eugenio at Systemic: "For
exoplanetary systems, the reference plane is the plane of the sky. An
orbit with i=0 would appear face-on as seen from earth. For i=90, the
orbit is edge-on. For i=60, the orbital plane is tilted 30 degrees from
the line joining the Earth (or the Sun) and the distant star." The planet
masses produced by the Systemic Console assume an inclination of 90
degrees and this is the default. If another value of inclination is
provided then the planet masses are multiplied by 1/sin(inclination). Planet masses are in Jupiter masses.
- Strobe: This will lock the display frequency to the number of
days specified. Set this to the period of a planet and the planet will
appear static. This can be used to show up resonance. You may need to
adjust the period for best results because the actual period of a planet
may vary or be different from that specified in the fit file.
- Focus: If a valid planet number is placed in this field then
the coordinates will be rotated so that this planet is always in the same
direction. This can reveal Trojan, Horseshoe or other 1:1 resonant
behaviour.
- Method: Select the integration method. The default Yoshida 6th
order will probably provide the best combination of speed and accuracy.
- Star: If this is checked the star will remain static in the
centre of the screen.
- Barycentre: If this is checked the system barycentre will be in
the centre of the screen. The star and planet orbits may 'wobble'.
Simulation Page:
- The star will appear with the name "Star". The planets will appear with
the names Planet1, Planet2 etc in the sequence they are defined in the fit
file.
- Click Stop to stop/start the motion.
- Left/Right click Speed to increase/decrease simulation speed.
- Left/Right click Zoom to zoom in/out.
- Left/Right click Tilt to tilt the system up/down.
- Left/Right click Rotate to rotate the system.
- Click Back to reverse direction.
- Click Orbits to see orbits drawn (from osculating
elements calculated after each integration step). These may not always work
especially if orbits are very unstable.
- Click Info to toggle the top line information and planet names.
Information Line:
- Int. Step is the size of the integration step in days.
- body-body shows which two bodies are determining the integration step.
- Display Step is the number of days between display updates.
- Rel.Energy is the (change in energy)/(original energy) of the system.
- J=nnnn.nnn is the Julian date, starting with the date in the fit file.
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