Overhauled initial conditions generator for add_solar_system_body. Ca…

…n more robustly retrieve initial conditions for many more bodies in the solar system, including physical properties like mass, radius, and rotation rates if they exist. Updated the Basic_Simulation example to reflect the new capabilities.

examples/Basic_Simulation/initial_conditions.py

@@ -42,7 +42,13 @@
 rng = default_rng(seed=123)
 
 # Add the modern planets and the Sun using the JPL Horizons Database.
-sim.add_solar_system_body(["Sun","Mercury","Venus","Earth","Mars","Jupiter","Saturn","Uranus","Neptune","Pluto"])
+sim.add_solar_system_body(["Sun","Mercury","Venus","Earth","Mars","Jupiter","Saturn","Uranus","Neptune"])
+
+# Add in some main belt asteroids
+sim.add_solar_system_body(name=["Ceres","Vesta","Pallas","Hygiea"])
+
+# Add in some big KBOs
+sim.add_solar_system_body(name=["Pluto","Eris","Sedna","Haumea","Makemake","Quaoar","Orcus","Gonggong","Salacia"])
 
 # Add 5 user-defined massive bodies.
 npl         = 5

python/swiftest/swiftest/constants.py

@@ -11,6 +11,8 @@
 
 import numpy as np
 import astropy.constants as const
+import astropy.units as u
+from astropy.coordinates import SkyCoord
 
 # Constants in SI units
 GC = const.G.value[()]
@@ -27,4 +29,6 @@
 # Solar oblatenes values: From Mecheri et al. (2004), using Corbard (b) 2002 values (Table II)
 J2Sun = 2.198e-7
 J4Sun = -4.805e-9
+rotpoleSun = SkyCoord(ra=286.13 * u.degree, dec=63.87 * u.degree).cartesian
+rotSun = (360.0 / 25.05) / JD2S  * rotpoleSun