def add_comets(star, m_comets, n_comets, q_min, a_min, a_max, seed):
#bodies.position -= star.position
#bodies.velocity -= star.velocity
cloud_xyz = generate_initial_oort_cloud(star.mass, n_comets, q_min, a_min,
a_max, seed)
masses = new_salpeter_mass_distribution(n_comets, 0.1 | units.MSun,
100 | units.MSun)
masses = m_comets * masses / masses.sum()
print("total mass in comets: M=", masses.sum().in_(units.MEarth))
comets = Particles(n_comets)
comets.mass = masses
comets.name = "comet"
comets.host = star
comets.x = cloud_xyz[:, 2] | units.au
comets.y = cloud_xyz[:, 3] | units.au
comets.z = cloud_xyz[:, 4] | units.au
comets.vx = cloud_xyz[:, 5] | 2 * numpy.pi * units.au / units.yr
comets.vy = cloud_xyz[:, 6] | 2 * numpy.pi * units.au / units.yr
comets.vz = cloud_xyz[:, 7] | 2 * numpy.pi * units.au / units.yr
comets.position += star.position
comets.velocity += star.velocity
return comets
def construct_particle_set_from_orbital_elements(name,
mass,
a,
ecc,
inc,
Ma,
Aop,
LoAn,
Mparent=1 | units.MSun):
print("length:", len(a), len(ecc), len(inc), len(Ma), len(Aop), len(LoAn),
len(name))
p = Particles(len(a))
print(name)
p.name = name
p.type = "asteroid"
p.host = "Sun"
p.mass = mass
from orbital_elements_to_cartesian import orbital_elements_to_pos_and_vel
from orbital_elements_to_cartesian import orbital_period
from amuse.ext.orbital_elements import new_binary_from_orbital_elements
for i in range(len(p)):
Ta = True_anomaly_from_mean_anomaly(numpy.rad2deg(Ma[i]), ecc[i])
b = new_binary_from_orbital_elements(Mparent,
p[i].mass,
a[i],
ecc[i],
Ta,
inc[i],
LoAn[i],
Aop[i],
G=constants.G)
p[i].position = b[1].position - b[0].position
p[i].velocity = b[1].velocity - b[0].velocity
rho = 2.0 | units.g / units.cm**3
p.radius = (p.mass / rho)**(1. / 3.)
return p
