def make_giant_molecular_clouds(Ngmc):
N_thick_disk = int(0.5 * Ngmc)
N_thin_disk = int(0.5 * Ngmc)
converter = nbody_system.nbody_to_si(1.e+8 | units.MSun, 1.0 | units.kpc)
from amuse.ext.protodisk import ProtoPlanetaryDisk
Rin = 3.5 | units.kpc
Rout = 7.5 | units.kpc
masses = new_powerlaw_mass_distribution(N_thick_disk,
alpha=-1.6,
mass_min=1.0e+3 | units.MSun,
mass_max=1.0e+8 | units.MSun)
MGMCs = masses.sum()
MWG = MilkyWay_galaxy()
v_inner = MWG.vel_circ(Rout)
MGalaxy = v_inner**2 * Rout / constants.G
print("Masses:", MGMCs.in_(units.MSun), MGalaxy.in_(units.MSun), \
MGMCs/MGalaxy)
GMCs = ProtoPlanetaryDisk(len(masses),
convert_nbody=converter,
Rmin=Rin.value_in(units.kpc),
Rmax=Rout.value_in(units.kpc),
q_out=30.0,
discfraction=MGMCs / MGalaxy).result
#second population of GMCs
masses = new_powerlaw_mass_distribution(len(GMCs),
alpha=-1.6,
mass_min=1.e+3 | units.MSun,
mass_max=1.0e+8 | units.MSun)
GMCs.mass = masses
MGMCs = masses.sum()
thin_disk_GMCs = ProtoPlanetaryDisk(N_thin_disk,
convert_nbody=converter,
Rmin=Rin.value_in(units.kpc),
Rmax=2 * Rout.value_in(units.kpc),
q_out=10.0,
discfraction=MGMCs / MGalaxy).result
thin_disk_GMCs.masses = masses
GMCs.add_particles(thin_disk_GMCs)
GMCs.velocity *= -1
GMCs.mass = new_powerlaw_mass_distribution(len(GMCs),
alpha=-1.6,
mass_min=1.e+3 | units.MSun,
mass_max=1.0e+8 | units.MSun)
print("v=", v_inner.in_(units.kms))
print("GMC mass=", GMCs.mass.sum().in_(units.MSun))
for gi in range(len(GMCs)):
r = GMCs[gi].position.length()
vc = MWG.vel_circ(r)
GMCs[gi].velocity = GMCs[gi].velocity * (vc /
GMCs[gi].velocity.length())
return GMCs
def add_debris_disk(star,
ndisk_per_MSun,
fdisk,
masteroid,
Rmin,
Rmax,
alpha=1.5,
Q=1.0):
Ndisk = int(ndisk_per_MSun * star.mass.value_in(units.MSun))
print("Run with Ndisk = ", Ndisk)
converter = nbody_system.nbody_to_si(star.mass, Rmin)
disk = ProtoPlanetaryDisk(Ndisk,
convert_nbody=converter,
densitypower=alpha,
Rmin=Rmin / Rmin,
Rmax=Rmax / Rmin,
q_out=Q,
discfraction=fdisk).result
disk.mass = masteroid
disk.name = "asteroid"
disk.type = "debris"
disk.host = star.key
disk.position += star.position
disk.velocity += star.velocity
return disk
def make_giant_molecular_clouds(Ngmc):
N_thick_disk = int(0.5*Ngmc)
N_thin_disk = int(0.5*Ngmc)
converter=nbody_system.nbody_to_si(1.e+8|units.MSun, 1.0|units.kpc)
from amuse.ext.protodisk import ProtoPlanetaryDisk
Rin = 3.5 | units.kpc
Rout = 7.5 | units.kpc
masses = new_powerlaw_mass_distribution(N_thick_disk, alpha=-1.6,
mass_min=1.0e+3|units.MSun,
mass_max=1.0e+8|units.MSun)
MGMCs = masses.sum()
MWG = MilkyWay_galaxy()
v_inner = MWG.vel_circ(Rout)
MGalaxy = v_inner**2*Rout/constants.G
print "Masses:", MGMCs.in_(units.MSun), MGalaxy.in_(units.MSun), \
MGMCs/MGalaxy
GMCs = ProtoPlanetaryDisk(len(masses), convert_nbody=converter,
Rmin=Rin.value_in(units.kpc),
Rmax=Rout.value_in(units.kpc),
q_out=30.0, discfraction=MGMCs/MGalaxy).result
#second population of GMCs
masses = new_powerlaw_mass_distribution(len(GMCs), alpha=-1.6,
mass_min=1.e+3|units.MSun,
mass_max=1.0e+8|units.MSun)
GMCs.mass = masses
MGMCs = masses.sum()
thin_disk_GMCs = ProtoPlanetaryDisk(N_thin_disk, convert_nbody=converter,
Rmin=Rin.value_in(units.kpc),
Rmax=2*Rout.value_in(units.kpc),
q_out=10.0, discfraction=MGMCs/MGalaxy).result
thin_disk_GMCs.masses = masses
GMCs.add_particles(thin_disk_GMCs)
GMCs.velocity *= -1
GMCs.mass = new_powerlaw_mass_distribution(len(GMCs), alpha=-1.6,
mass_min=1.e+3|units.MSun,
mass_max=1.0e+8|units.MSun)
print "v=", v_inner.in_(units.kms)
print "GMC mass=", GMCs.mass.sum().in_(units.MSun)
for gi in range(len(GMCs)):
r = GMCs[gi].position.length()
vc = MWG.vel_circ(r)
GMCs[gi].velocity = GMCs[gi].velocity * (vc/GMCs[gi].velocity.length())
return GMCs
def initial_conditions(Q, N, Rmax, diskmassfrac, seed_disk):
'''
returns Sun + 8 planets, as well as a disk around Neptune
'''
#get the solar system objects
sun_and_planets = new_solar_system()
#throw out Pluto, get Neptune object from new_solar_system
N_particles = len(sun_and_planets)
sun_and_planets = sun_and_planets[:N_particles - 1]
Nep_ind = len(sun_and_planets) - 1
Sun = sun_and_planets[0]
Neptune = sun_and_planets[Nep_ind]
#hill radius of Neptune
a_Neptune = np.sqrt(Neptune.x**2 + Neptune.y**2 + Neptune.z**2)
Neptune_Hill = a_Neptune * (Neptune.mass / Sun.mass)**(1 / 3.)
#get the disk with appropriate Salpeter mass distribution
#Salpeter mass function with a range of 1 order of magnitude
mmin = 0.0005 * Neptune.mass #mmax goes to 0.005
masses = new_salpeter_mass_distribution(N,
mass_min=mmin,
mass_max=(10 * mmin))
#set up converter, protoplanetary disk gas particles
np.random.seed(seed_disk) #random seed for the disk
converter_gas = nbody_system.nbody_to_si(Neptune.mass, Rmax | units.AU)
gas = ProtoPlanetaryDisk(N,
convert_nbody=converter_gas,
Rmin=converter_gas.to_nbody(Neptune_Hill).number,
Rmax=converter_gas.to_nbody(Rmax
| units.AU).number,
q_out=Q,
discfraction=diskmassfrac).result
#attribute Salpeter masses to the gas
gas.mass = masses
#move disk to Neptune's phase space coordinates
gas.x += Neptune.x
gas.y += Neptune.y
gas.z += Neptune.z
gas.vx += Neptune.vx
gas.vy += Neptune.vy
gas.vz += Neptune.vz
return sun_and_planets, gas
