def new_system(star_mass=1 | units.MSun,
star_radius=1 | units.RSun,
disk_minimum_radius=0.05 | units.AU,
disk_maximum_radius=10 | units.AU,
disk_mass=20 | MEarth,
accurancy=0.0001,
planet_density=3 | units.g / units.cm**3,
rng=None,
kepler=None):
central_particle = Particle()
central_particle.mass = star_mass
central_particle.position = (0, 0, 0) | units.AU
central_particle.velocity = (0, 0, 0) | units.kms
central_particle.radius = star_radius
central_particle.name = "star"
central_particle.type = "star"
central_particle.id = 0
if rng is None:
rng = numpy.random
converter = nbody_system.nbody_to_si(1 | units.MSun, 1 | units.AU)
if kepler is None:
kepler = Kepler(converter)
kepler.initialize_code()
m, r, f = new_planet_distribution(disk_minimum_radius, disk_maximum_radius,
disk_mass, accurancy)
planets = make_planets(central_particle,
m,
r,
density=planet_density,
phi=0,
theta=None,
kepler=kepler,
rng=rng)
planets.name = "planet"
planets.type = "planet"
for i in range(len(planets)):
planets[i].id = i
central_particle.planets = planets
kepler.stop()
p = Particles()
p.add_particle(central_particle)
return p
def get_moons_for_planet(planet, delta_JD=0. | units.day):
"""
The Earth's moon
as for JD = 2457099.500000000 = A.D. 2015-Mar-18 00:00:00.0000 (CT)
https://ssd.jpl.nasa.gov/?sat_elem
"""
data = numpy.array([tuple(entry) for entry in _lunar_data],
dtype=[('planet_name', 'S10'), ('name', 'S10'),
('mass', '<f8'), ('radius', '<f8'),
('semimajor_axis', '<f8'),
('eccentricity', '<f8'),
('argument_of_peri', '<f8'),
('mean_anomaly', '<f8'), ('inclination', '<f8'),
('longitude_oan', '<f8')])
moon_data = data[data['planet_name'] == planet.name.encode('UTF-8')]
print("Planet=", planet.name, "moon=", moon_data["name"])
moons = Particles()
if len(moon_data["name"]):
print(len(moon_data["name"]))
for moon in moon_data:
#Ignore the moon for now, because it's complicated
if planet.name == "EarthMoon":
planet.mass -= moon["mass"] * 1.e+16 | units.kg
planet.name = "Earth"
#print moon
r, v = get_position(planet.mass,
moon["mass"] * 1.e+16 | units.kg,
moon["eccentricity"],
moon["semimajor_axis"] | units.km,
numpy.deg2rad(moon["mean_anomaly"]),
numpy.deg2rad(moon["inclination"]),
numpy.deg2rad(moon["longitude_oan"]),
numpy.deg2rad(moon["argument_of_peri"]),
delta_t=delta_JD)
single_moon = Particle()
single_moon.type = "moon"
single_moon.name = moon["name"]
single_moon.mass = moon["mass"] * 1.e+16 | units.kg
single_moon.hostname = moon["planet_name"]
single_moon.radius = moon["radius"] | units.km
single_moon.position = r
single_moon.position += planet.position
single_moon.velocity = v
single_moon.velocity += planet.velocity
moons.add_particle(single_moon)
return moons
def old_new_solar_system():
"""
Create initial conditions describing the solar system. Returns a single
particle set containing the sun, planets and Pluto. The model is centered at
the origin (center-of-mass(-velocity) coordinates).
Defined attributes:
name, mass, radius, x, y, z, vx, vy, vz
"""
sun = Particle()
sun.name = 'SUN'
sun.mass = 1.0 | units.MSun
sun.radius = 1.0 | units.RSun
planets = _planets_only()
particles = Particles()
particles.add_particle(sun)
particles.add_particles(planets)
particles.move_to_center()
return particles
def get_moons_for_planet(planet, delta_JD=0.|units.day):
"""
The Earth's moon
as for JD = 2457099.500000000 = A.D. 2015-Mar-18 00:00:00.0000 (CT)
https://ssd.jpl.nasa.gov/?sat_elem
"""
data = numpy.array([tuple(entry) for entry in _lunar_data],
dtype=[('planet_name','S10'), ('name','S10'),
('mass','<f8'), ('radius','<f8'), ('semimajor_axis','<f8'),
('eccentricity','<f8'), ('argument_of_peri','<f8'),
('mean_anomaly','<f8'), ('inclination','<f8'), ('longitude_oan','<f8')])
moon_data = data[data['planet_name']==planet.name]
print "Planet=", planet.name, "moon=", moon_data["name"]
moons = Particles()
if len(moon_data["name"]):
print len(moon_data["name"])
for moon in moon_data:
#print moon
r, v = get_position(planet.mass,
moon["mass"] * 1.e+16 | units.kg,
moon["eccentricity"],
moon["semimajor_axis"]|units.km,
numpy.deg2rad(moon["mean_anomaly"]),
numpy.deg2rad(moon["inclination"]),
numpy.deg2rad(moon["longitude_oan"]),
numpy.deg2rad(moon["argument_of_peri"]),
delta_t=delta_JD)
single_moon = Particle()
single_moon.type = "moon"
single_moon.name = moon["name"]
single_moon.mass = moon["mass"] * 1.e+16 | units.kg
single_moon.hostname = moon["planet_name"]
single_moon.radius = moon["radius"] | units.km
single_moon.position = r
single_moon.position += planet.position
single_moon.velocity = v
single_moon.velocity += planet.velocity
moons.add_particle(single_moon)
return moons
def get_sun_and_planets(delta_JD=0.|units.day):
"""
eight planets of the Solar System
as for JD = 2457099.500000000 = A.D. 2015-Mar-18 00:00:00.0000 (CT)
http://ssd.jpl.nasa.gov/horizons.cgi
"""
planets = Particles(8)
# mass
planets.mass = [3.302e23,
48.685e23,
5.97219e24,
6.4185e23,
1898.13e24,
5.68319e26,
86.8103e24,
102.41e24] | units.kg
# eccentricity
planets_ecc = [2.056263501026885E-01,
6.756759719005901E-03,
1.715483324953308E-02,
9.347121362500883E-02,
4.877287772914470E-02,
5.429934603664216E-02,
4.911406962716518E-02,
8.494660388602767E-03]
# semi-major axis
planets_semi = [3.870989725156447E-01,
7.233252880006816E-01,
1.000816989613834E+00,
1.523624142457679E+00,
5.203543088590996E+00,
9.547316304899041E+00,
1.915982879739036E+01,
2.997013749028780E+01] | units.AU
# mean anomaly [degrees]
planets_mean_anomaly = [2.256667460183225E+02,
3.096834722926926E+02,
6.970055236286768E+01,
5.013506750245609E+01,
1.213203242081277E+02,
1.423311616732398E+02,
2.079860620353052E+02,
2.712246916734600E+02]
planets_mean_anomaly = numpy.array(planets_mean_anomaly) * pi_over_180
# inclination [IN degrees]
planets_inclination = [7.004026765179669E+00,
3.394480103844425E+00,
3.563477431351056E-03,
1.848403408106458E+00,
1.303457729562742E+00,
2.488017444885577E+00,
7.728000142736371E-01,
1.767720502209091E+00]
planets_inclination = numpy.array(planets_inclination) * pi_over_180
# Longitude of Ascending Node [OM degrees]
planets_longitude = [4.831163083479358E+01,
7.663982595051040E+01,
1.775515437672556E+02,
4.951282677064384E+01,
1.005036717671826E+02,
1.135683875842263E+02,
7.388411509910506E+01,
1.317497218434830E+02]
planets_longitude = numpy.array(planets_longitude) * pi_over_180
# Argument of Perihelion [W degrees]
planets_argument = [2.916964171964058E+01,
5.469102797401222E+01,
2.877495001117996E+02,
2.865420083537150E+02,
2.740725976811202E+02,
3.398666856578898E+02,
9.666856264946740E+01,
2.951871807292030E+02]
planets_argument = numpy.array(planets_argument) * pi_over_180
planets.name = ['Mercury',
'Venus',
'Earth',
'Mars',
'Jupiter',
'Satrun',
'Uranus',
'Neptune']
### to compare with JPL, mass of the Sun needs to be rescaled
#mg_nasa = 1.32712440018e20 | (units.m**3 / units.s**2)
#g_nasa = 6.67259e-11 | (units.m**3 / units.kg / units.s**2)
#ms = mg_nasa / g_nasa
sun = Particle()
sun.name = 'Sun'
#sun.mass = ms
sun.mass = 1.0 | units.MSun
sun.position = [0.,0.,0.] | units.AU
sun.velocity = [0.,0.,0.] | units.kms
# get the position and velocity vectors relative to sun
# by evolving in Kepler
for i,ecc_i in enumerate(planets_ecc):
r, v = get_position(sun.mass,
planets[i].mass,
planets_ecc[i],
planets_semi[i],
planets_mean_anomaly[i],
planets_inclination[i],
planets_longitude[i],
planets_argument[i],
delta_t=delta_JD)
planets[i].position = r
planets[i].velocity = v
return sun, planets
