def add_comet_objects(pre_tack_giants_system, N_objects, comet_positions,
comet_velocities):
for i in tqdm(range(N_objects)):
comet = Particles(1)
comet.name = "OORT_" + str(i)
comet.mass = 0.0 | units.MSun #Take massless test particles
comet.radius = 0.0 | units.RSun
comet.position = (comet_positions[i, 0], comet_positions[i, 1],
comet_positions[i, 2])
comet.velocity = (comet_velocities[i, 0], comet_velocities[i, 1],
comet_velocities[i, 2])
comet.density = 0.0 | (units.MSun / (units.RSun**3))
pre_tack_giants_system.add_particle(comet)
z_comp = np.arctan(
100 / 8500.
) #Determining the z-component of the sun's trajectory around the galactic center
for i in range(len(pre_tack_giants_system)
): #adding the sun's trajectory around the galactic center
pre_tack_giants_system[i].position += (1, 0, 0) * (8.5 | units.kpc)
pre_tack_giants_system[i].velocity += (0, np.sqrt(1 - z_comp**2),
z_comp) * (220 | units.kms)
return pre_tack_giants_system
def merge_two_particles(gravity, particles_in_encounter):
new_particle = Particles(1)
new_particle.mass = particles_in_encounter.total_mass()
new_particle.position = particles_in_encounter.center_of_mass()
new_particle.velosity = particles_in_encounter.center_of_mass_velocity()
new_particle.radius = particles_in_encounter.radius.sum()
gravity.particles.add_particles(new_particle)
gravity.particles.remove_particles(particles_in_encounter)
def create_system():
system = new_solar_system()
system = system[system.mass > 10**-5 | units.MSun] # Takes gas giants and Sun only
system.move_to_center()
sun = Particles(1)
sun.name = "Sun"
sun.mass = 1.0 | units.MSun
sun.radius = 1.0 | units.RSun
sun.position = (0, 0, 0) | units.AU
sun.velocity = (0, 0, 0) | units.kms
sun.density = 3*sun.mass/(4*np.pi*sun.radius**3)
names = ["Jupiter", "Saturn", "Uranus", "Neptune"]
masses = [317.8, 90, 15, 17] | units.MEarth
radii = [0.10049, 0.083703, 0.036455, 0.035392] | units.RSun
semis = [5.4, 7.1, 10.5, 13] | units.AU #[3.5, 4.9, 6.4, 8.4]
trues = [0, 90, 180, 270]| units.deg#np.random.uniform(0, 360, 4) | units.deg
longs = np.random.uniform(0, 360, 4) | units.deg
args = np.random.uniform(0, 360, 4) | units.deg
for i in range(4):
orbital_elements = get_orbital_elements_from_binary(system[0]+ system[i+1], G=constants.G)
eccentricity, inclination = 0, orbital_elements[5]
sun_and_plan = new_binary_from_orbital_elements(sun[0].mass, masses[i],
semis[i], 0, trues[i], inclination, longs[i], args[i], G=constants.G)
planet = Particles(1)
planet.name = system[i+1].name
planet.mass = system[i+1].mass
planet.radius = system[i+1].radius # This is purely non-zero for collisional purposes
planet.position = (sun_and_plan[1].x-sun_and_plan[0].x, sun_and_plan[1].y-sun_and_plan[0].y, sun_and_plan[1].z-sun_and_plan[0].z)
planet.velocity = (sun_and_plan[1].vx-sun_and_plan[0].vx, sun_and_plan[1].vy-sun_and_plan[0].vy, sun_and_plan[1].vz-sun_and_plan[0].vz)
planet.density = 3*planet.mass/(4*np.pi*planet.radius**3)
sun.add_particle(planet)
return sun
def create_pre_tack_giants_system():
#Create a pre_tack_giants_system by first recreating the sun.
pre_tack_giants_system = Particles(1)
pre_tack_giants_system[0].name = "Sun"
pre_tack_giants_system[0].mass = 1.0 | units.MSun
pre_tack_giants_system[0].radius = 1.0 | units.RSun
pre_tack_giants_system[0].position = (0, 0, 0) | units.AU
pre_tack_giants_system[0].velocity = (0, 0, 0) | units.kms
pre_tack_giants_system[0].density = 3 * pre_tack_giants_system[0].mass / (
4 * np.pi * pre_tack_giants_system[0].radius**3)
#The pre tack orbital elements for the planets as below
names = ["Jupiter", "Saturn", "Uranus", "Neptune"]
masses = np.array([317.8, 30, 5, 5]) | units.MEarth
radii = np.array([0.10049, 0.083703, 0.036455, 0.035392]) | units.RSun
a = np.array([3.5, 4.5, 6.013, 8.031]) | units.AU
inclinations = np.random.uniform(-5, 5, 4) | units.deg
true_anomalies = np.random.uniform(0, 360, 4) | units.deg
longs_of_ascending_node = np.random.uniform(0, 360, 4) | units.deg
args_of_periapsis = np.random.uniform(0, 360, 4) | units.deg
#Create the four planets as binaries with the sun and add them to the pre_tack_giants_system
for i in range(4):
sun_and_planet = new_binary_from_orbital_elements(
pre_tack_giants_system[0].mass,
masses[i],
a[i],
0,
true_anomalies[i],
inclinations[i],
longs_of_ascending_node[i],
args_of_periapsis[i],
G=constants.G)
planet = Particles(1)
planet.name = names[i]
planet.mass = masses[i]
planet.radius = radii[
i] # This is purely non-zero for collisional purposes
planet.position = (sun_and_planet[1].x - (0 | units.AU),
sun_and_planet[1].y - (0 | units.AU),
sun_and_planet[1].z - (0 | units.AU))
planet.velocity = (sun_and_planet[1].vx - (0 | units.kms),
sun_and_planet[1].vy - (0 | units.kms),
sun_and_planet[1].vz - (0 | units.kms))
planet.density = 3 * planet.mass / (4 * np.pi * planet.radius**3)
pre_tack_giants_system.add_particle(planet)
return pre_tack_giants_system
def add_comet_objects(pre_tack_giants_system, N_objects, comet_positions,
comet_velocities):
for i in tqdm(range(N_objects)):
comet = Particles(1)
comet.name = "OORT_" + str(i)
comet.mass = 0.0 | units.MSun #Take massless test particles
comet.radius = 0.0 | units.RSun
comet.position = (comet_positions[i, 0], comet_positions[i, 1],
comet_positions[i, 2])
comet.velocity = (comet_velocities[i, 0], comet_velocities[i, 1],
comet_velocities[i, 2])
comet.density = 0.0 | (units.MSun / (units.RSun**3))
pre_tack_giants_system.add_particle(comet)
return pre_tack_giants_system
def add_comet_objects(system, N_objects, rand_pos, rand_vel):
for i in tqdm(range(N_objects)):
oort = Particles(1)
oort.name = "OORT_" + str(i)
oort.mass = 0.0 | units.MSun
oort.radius = (2.3 | units.km).in_(units.RSun) # This is purely non-zero for collisional purposes
oort.position = (rand_pos[i, 0], rand_pos[i, 1], rand_pos[i, 2])
oort.velocity = (rand_vel[i, 0], rand_vel[i, 1], rand_vel[i, 2])
system.add_particle(oort)
for particle in system: #So that Mercury will work
particle.density = 3*particle.mass/(4*np.pi*particle.radius**3)
return system
def merge_two_bodies(bodies, particles_in_encounter):
com_pos = particles_in_encounter.center_of_mass()
com_vel = particles_in_encounter.center_of_mass_velocity()
d = (particles_in_encounter[0].position - particles_in_encounter[1].position)
v = (particles_in_encounter[0].velocity - particles_in_encounter[1].velocity)
print("Actually merger occurred:")
print("Two objects (M=",particles_in_encounter.mass.in_(units.MSun),
") collided with d=", d.length().in_(units.au))
#time.sleep(10)
new_particle=Particles(1)
new_particle.mass = particles_in_encounter.total_mass()
new_particle.position = com_pos
new_particle.velocity = com_vel
new_particle.radius = ((particles_in_encounter.radius**3).sum())**(1./3.) # New radius cannot simply be summed
bodies.add_particles(new_particle)
bodies.remove_particles(particles_in_encounter)
def create_post_tack_giants_system():
#Create the present day solar system and keep only the sun and the giants
present_day_solar_system = new_solar_system()
present_day_solar_system = present_day_solar_system[present_day_solar_system.mass > 10**-5 | units.MSun] # Takes gas giants and Sun only
present_day_solar_system.move_to_center()
#Create a post_tack_giants_system by first recreating the sun.
post_tack_giants_system = Particles(1)
post_tack_giants_system[0].name = "Sun"
post_tack_giants_system[0].mass = 1.0 | units.MSun
post_tack_giants_system[0].radius = 1.0 | units.RSun
post_tack_giants_system[0].position = (0, 0, 0) | units.AU
post_tack_giants_system[0].velocity = (0, 0, 0) | units.kms
#The post tack orbital elements for the planets as below
a = np.array([5.4, 7.1, 10.5, 13]) | units.AU
true_anomalies = np.random.uniform(0, 360, 4) | units.deg
long_of_ascending_node = np.random.uniform(0, 360, 4) | units.deg
args_of_periapsis = np.random.uniform(0, 360, 4) | units.deg
#Create the four planets as binaries with the sun and add them to the post_tack_giants_system
for i in range(4):
orbital_elements = get_orbital_elements_from_binary(present_day_solar_system[0]+ present_day_solar_system[i+1], G=constants.G)
inclination = orbital_elements[5] #Make sure we have a sensable inclination for the giants
sun_and_planet = new_binary_from_orbital_elements(post_tack_giants_system.mass[0], present_day_solar_system[i+1].mass,
a[i], 0, true_anomalies[i], inclination, long_of_ascending_node[i], args_of_periapsis[i], G=constants.G)
planet = Particles(1)
planet.name = present_day_solar_system[i+1].name
planet.mass = present_day_solar_system[i+1].mass
planet.radius = present_day_solar_system[i+1].radius
planet.position = (sun_and_planet[1].x-sun_and_planet[0].x, sun_and_planet[1].y-sun_and_planet[0].y, sun_and_planet[1].z-sun_and_planet[0].z)
planet.velocity = (sun_and_planet[1].vx-sun_and_planet[0].vx, sun_and_planet[1].vy-sun_and_planet[0].vy, sun_and_planet[1].vz-sun_and_planet[0].vz)
post_tack_giants_system.add_particle(planet)
return post_tack_giants_system