CelesToolsPython tools to help you with your celestial mechanics/

orbital dynamics problems

Russell Deitrick

where?

• git the most up-to-date version: github.com/deitrr/celestools

• or go to the VPL website: vplapps.astro.washington.edu/vpltools.html

using CelesTools• view the jupyter notebook example:

• jupyter notebook Examples.ipynb

• make sure to set your python path in .bash_profile or .bashrc:

• export PYTHONPATH=${PYTHONPATH}:/Users/russell/Code/celestools

• importing CelesTools:

• import celestools as ct

these are solar system coordinates “osculating” elements

let’s convert them to cartesian coordinates

sometimes useful, especially for N-body code also, you can do the inverse calculation

convert to invariable plane coordinatesoften useful for analysis and understanding

I used these in Deitrick et al. 2015with ~17 years of observations, we know υ And b’s period very well, and HNBody doesn’t do this conversion very accurately

calculate the Hill stability criterionusually a good measure of “true” stability for a 2 planet

system (Barnes & Greenberg 2006)

Sun-Jupiter-Saturn example

other things you can calculate/do…

• total angular momentum

• total orbital energy

• mutual inclinations

• radial velocities

• period ←→ semi-major axis

• convert b/w coordinates (astrocentric, barycentric, jacobian)

• what else would be helpful?

use Hill stability, RV amplitude functions, etc., when setting up simulations

forthcoming work on Proxima Cen b (Fleming et al.)

RV semi-amplitude [m/s]

mutual inclination of υ And c and dDeitrick+ 2015

units

• a lot of the functions take keyword args: inUnits, outUnits, angUnits

• ‘iau’, ‘mks’, or ‘cgs’: unit systems

• (iau: astronomical units, solar masses, days)

• ‘deg’ or ‘rad’: angle units

deitrr@uw.edu github.com/deitrr/celestools

CelesTools is very much a work in progress! In particular, a lot of functions don’t have good

documentation or handle units yet.

Feature requests? Weird errors?

Notice a mistake? Contact me or open an issue: