def new_disk_with_bump(Mstar=1 | units.MSun,
Ndisk=100,
Mdisk=0.9 | units.MSun,
Rmin=1.0 | units.AU,
Rmax=100.0 | units.AU,
Mbump=0.1 | units.MSun,
Rbump=10.0 | units.AU,
abump=10 | units.AU):
converter = nbody_system.nbody_to_si(Mdisk, Rmin)
from amuse.ext.protodisk import ProtoPlanetaryDisk
bodies = ProtoPlanetaryDisk(Ndisk,
convert_nbody=converter,
densitypower=1.5,
Rmin=1,
Rmax=Rmax / Rmin,
q_out=1.0,
discfraction=1.0).result
Mdisk = bodies.mass.sum()
bodies.move_to_center()
com = bodies.center_of_mass()
mm = Mdisk / float(Ndisk)
Nbump = Mbump / mm
bump = new_plummer_gas_model(Nbump,
convert_nbody=nbody_system.nbody_to_si(
Mbump, Rbump))
bump.x += abump
r_bump = abump
inner_particles = bodies.select(lambda r: (com - r).length() < abump,
["position"])
M_inner = inner_particles.mass.sum() + Mstar
v_circ = (constants.G * M_inner *
(2. / r_bump - 1. / abump)).sqrt().value_in(units.kms)
bump.velocity += [0, v_circ, 0] | units.kms
bodies.add_particles(bump)
bodies = bodies.select(lambda r: (com - r).length() > Rmin, ["position"])
bodies = bodies.select(lambda r: (com - r).length() < Rmax, ["position"])
print("Nbump=", Ndisk, Mbump, Rbump, Nbump)
print("Mass =", Mstar, Mdisk,
bodies.mass.sum().in_(units.MSun),
bodies.mass.sum() / Mstar)
print("X-min/max:", min(bodies.x), max(bodies.x))
bodies = bodies.select(lambda r: r.length() < 1.0 * Rmax, ["position"])
print("X-min/max:", min(bodies.x), max(bodies.x))
return bodies
def new_disk_with_bump(Mstar = 1|units.MSun,
Ndisk=100, Mdisk=0.9|units.MSun,
Rmin=1.0|units.AU, Rmax=100.0|units.AU,
Mbump=0.1|units.MSun,Rbump=10.0|units.AU,
abump=10|units.AU):
converter=nbody_system.nbody_to_si(Mdisk, Rmin)
bodies = ProtoPlanetaryDisk(Ndisk, convert_nbody=converter,
densitypower=1.5,
Rmin=1.0,
Rmax=Rmax/Rmin,
q_out=1.0,
discfraction=1.0).result
Mdisk = bodies.mass.sum()
bodies.move_to_center()
com = bodies.center_of_mass()
mm = Mdisk/float(Ndisk)
Nbump = Mbump/mm
print "Nbump=", Mbump, Rbump, Nbump
print "Mass =", Mstar, Mdisk, bodies.mass.sum().in_(units.MSun), bodies.mass.sum()/Mstar
bump = new_plummer_gas_model(Nbump, convert_nbody=nbody_system.nbody_to_si(Mbump, Rbump))
bump.x += abump
r_bump = abump
inner_particles = bodies.select(lambda r: (com-r).length()<abump,["position"])
M_inner = inner_particles.mass.sum() + Mstar
v_circ = (constants.G*M_inner*(2./r_bump - 1./abump)).sqrt().value_in(units.kms)
bump.velocity += [0, v_circ, 0] | units.kms
bodies.add_particles(bump)
return bodies
def new_disk_with_bump(Mstar = 10|units.MSun,
Ndisk=100, Mdisk=1.0|units.MSun,
Rmin=1.0|units.AU, Rmax=100.0|units.AU,
Mbump=0.1|units.MSun,Rbump=5.0|units.AU,
abump=10|units.AU):
converter=nbody_system.nbody_to_si(Mstar, Rmin)
disk = ProtoPlanetaryDisk(Ndisk, convert_nbody=converter,
densitypower=1.5, Rmin=1, Rmax=Rmax/Rmin,
q_out=1.0, discfraction=Mdisk/Mstar).result
com = disk.center_of_mass()
# determine bump's local velocity
inner_particles = disk.select(lambda r: (com-r).length()
< abump,["position"])
M_inner = Mstar + inner_particles.mass.sum()
v_circ = (constants.G*M_inner*(2./abump - 1./abump)) \
.sqrt().value_in(units.kms)
# initialize bump
Nbump = int(Ndisk*Mbump/Mdisk)
bump = new_plummer_gas_model(Nbump,
convert_nbody=nbody_system.nbody_to_si(Mbump,
Rbump))
bump.x += abump
bump.velocity += [0, v_circ, 0] | units.kms
disk.add_particles(bump)
disk.move_to_center()
return disk
def main(N=1000, Lstar=100| units.LSun, boxsize=10| units.parsec,
rho=1.0| (units.amu/units.cm**3), t_end=0.1|units.Myr, n_steps=10):
ionization_fraction = 0.0
internal_energy = (9. |units.kms)**2
source=Particles(1)
source.position = (0, 0, 0) |units.parsec
source.flux = Lstar/(20. | units.eV)
source.luminosity = Lstar/(20. | units.eV)
source.rho = rho
source.xion = ionization_fraction
source.u = internal_energy
converter=nbody_system.nbody_to_si(1|units.MSun, boxsize)
ism = ProtoPlanetaryDisk(N, convert_nbody=converter,
densitypower=1.5,
Rmin=0.1,
Rmax=1,
q_out=1.0,
discfraction=1.0).result
ism = ism.select(lambda r: r.length()<0.5*boxsize,["position"])
gamma=5./3.
mu=1.| units.amu
Tinit = 10000|units.K
ism.u = 1/(gamma-1)*constants.kB * Tinit/mu
ism.rho = rho
ism.flux = 0. | units.s**-1
ism.xion = ionization_fraction
ism.h_smooth = 0 | units.AU
rad = SimpleXSplitSet(redirect="none")
# rad = SimpleX()
# rad = SPHRay()
rad.parameters.box_size=1.001*boxsize
rad.parameters.timestep=0.001 | units.Myr
rad.src_particles.add_particle(source)
rad.gas_particles.add_particles(ism)
channel_to_local_gas = rad.gas_particles.new_channel_to(ism)
write_set_to_file(ism, "rad.hdf5", 'hdf5')
time = 0.0 | t_end.unit
dt = t_end/float(n_steps)
while time<t_end:
time += dt
rad.evolve_model(time)
channel_to_local_gas.copy_attributes(["xion",])
write_set_to_file(ism, "rad.hdf5", 'hdf5')
print "Time=", time
print "min ionization:", rad.gas_particles.xion.min()
print "average Xion:", rad.gas_particles.xion.mean()
print "max ionization:", rad.gas_particles.xion.max()
rad.stop()
def main(N=1000,
Lstar=100 | units.LSun,
boxsize=10 | units.parsec,
rho=1.0 | (units.amu / units.cm**3),
t_end=0.1 | units.Myr,
n_steps=10):
ionization_fraction = 0.0
internal_energy = (9. | units.kms)**2
source = Particles(1)
source.position = (0, 0, 0) | units.parsec
source.flux = Lstar / (20. | units.eV)
source.luminosity = Lstar / (20. | units.eV)
source.rho = rho
source.xion = ionization_fraction
source.u = internal_energy
converter = nbody_system.nbody_to_si(1 | units.MSun, boxsize)
ism = ProtoPlanetaryDisk(N,
convert_nbody=converter,
densitypower=1.5,
Rmin=0.1,
Rmax=1,
q_out=1.0,
discfraction=1.0).result
ism = ism.select(lambda r: r.length() < 0.5 * boxsize, ["position"])
gamma = 5. / 3.
mu = 1. | units.amu
Tinit = 10000 | units.K
ism.u = 1 / (gamma - 1) * constants.kB * Tinit / mu
ism.rho = rho
ism.flux = 0. | units.s**-1
ism.xion = ionization_fraction
ism.h_smooth = 0 | units.AU
rad = SimpleXSplitSet(redirect="none")
# rad = SimpleX()
# rad = SPHRay()
rad.parameters.box_size = 1.001 * boxsize
rad.parameters.timestep = 0.001 | units.Myr
rad.src_particles.add_particle(source)
rad.gas_particles.add_particles(ism)
channel_to_local_gas = rad.gas_particles.new_channel_to(ism)
write_set_to_file(ism, "rad.hdf5", 'hdf5')
time = 0.0 | t_end.unit
dt = t_end / float(n_steps)
while time < t_end:
time += dt
rad.evolve_model(time)
channel_to_local_gas.copy_attributes([
"xion",
])
write_set_to_file(ism, "rad.hdf5", 'hdf5')
print("Time=", time)
print("min ionization:", rad.gas_particles.xion.min())
print("average Xion:", rad.gas_particles.xion.mean())
print("max ionization:", rad.gas_particles.xion.max())
rad.stop()
def main(Mstar=1 | units.MSun,
Ndisk=100,
Mdisk=0.9 | units.MSun,
Rmin=1.0 | units.AU,
Rmax=100.0 | units.AU,
Mbump=0.1 | units.MSun,
Rbump=10.0 | units.AU,
abump=10 | units.AU,
t_end=1,
n_steps=10):
converter = nbody_system.nbody_to_si(Mdisk, Rmin)
from amuse.ext.protodisk import ProtoPlanetaryDisk
bodies = ProtoPlanetaryDisk(Ndisk,
convert_nbody=converter,
densitypower=1.5,
Rmin=1.0,
Rmax=Rmax / Rmin,
q_out=1.0,
discfraction=1.0).result
Mdisk = bodies.mass.sum()
bodies.move_to_center()
com = bodies.center_of_mass()
mm = Mdisk / float(Ndisk)
Nbump = int(Mbump / mm)
bump = new_plummer_gas_model(Nbump,
convert_nbody=nbody_system.nbody_to_si(
Mbump, Rbump))
bump.x += abump
r_bump = abump
inner_particles = bodies.select(lambda r: (com - r).length() < abump,
["position"])
M_inner = inner_particles.mass.sum() + Mstar
v_circ = (constants.G * M_inner *
(2. / r_bump - 1. / abump)).sqrt().value_in(units.kms)
bump.velocity += [0, v_circ, 0] | units.kms
bodies.add_particles(bump)
star = Particles(1)
star.mass = Mstar
star.radius = Rmin
star.position = [0, 0, 0] | units.AU
star.velocity = [0, 0, 0] | units.kms
import math
P_bump = (abump**3 * 4 * math.pi**2 / (constants.G *
(Mbump + Mstar))).sqrt()
t_end *= P_bump
hydro = Gadget2(converter)
hydro.gas_particles.add_particles(bodies)
hydro.dm_particles.add_particles(star)
Etot_init = hydro.kinetic_energy + hydro.potential_energy + hydro.thermal_energy
particles = ParticlesSuperset([star, bodies])
particles.move_to_center()
particles.new_channel_to(hydro.particles).copy()
bodies.h_smooth = Rmin # for the plotting routine
channel_to_star = hydro.dm_particles.new_channel_to(star)
channel_to_bodies = hydro.gas_particles.new_channel_to(bodies)
write_set_to_file(star, "stars.hdf5", "hdf5")
write_set_to_file(bodies, "hydro.hdf5", "hdf5")
time = 0.0 | t_end.unit
dt = t_end / float(n_steps)
while time < t_end:
time += dt
hydro.evolve_model(time)
channel_to_star.copy()
channel_to_bodies.copy()
write_set_to_file(star, "stars.hdf5", "hdf5")
write_set_to_file(bodies, "hydro.hdf5", "hdf5")
star.radius = Rmin
from hydro_sink_particles import hydro_sink_particles
lost = hydro_sink_particles(star, bodies)
if len(lost) > 0:
hydro.particles.remove_particles(lost)
hydro.particles.synchronize_to(particles)
print("Disk=", hydro.model_time, len(bodies), len(lost),
lost.mass.sum(), star.mass)
Ekin = hydro.kinetic_energy
Epot = hydro.potential_energy
Eth = hydro.thermal_energy
Etot = Ekin + Epot + Eth
print("T=",
hydro.get_time(),
"M=",
hydro.gas_particles.mass.sum(),
end=' ')
print("E= ", Etot, "Q= ", (Ekin + Eth) / Epot, "dE=",
(Etot_init - Etot) / Etot)
print("Star=", hydro.model_time, star[0].mass, star[0].position)
hydro.stop()
def main(Mstar=1,
Ndisk=100,
Mdisk=0.001,
Rmin=1,
Rmax=100,
t_end=10,
n_steps=10,
filename="nbody.hdf5"):
# numpy.random.seed(111)
Mstar = Mstar | units.MSun
Mdisk = Mdisk | units.MSun
Rmin = Rmin | units.AU
Rmax = Rmax | units.AU
t_end = t_end | units.yr
# converter=nbody_system.nbody_to_si(Mdisk, Rmax)
converter = nbody_system.nbody_to_si(Mstar, Rmin)
disk = ProtoPlanetaryDisk(Ndisk,
convert_nbody=converter,
densitypower=1.5,
Rmin=Rmin.value_in(units.AU),
Rmax=Rmax.value_in(units.AU),
q_out=1.0,
discfraction=1.0).result
disk.move_to_center()
center_of_mass = disk.center_of_mass()
print(center_of_mass)
a_bump = 50
Rbump = 10 | units.AU
bump_location = center_of_mass + ([0, a_bump, 0] | units.AU)
bump_particles = disk.select(
lambda r: (center_of_mass - r).length() < Rbump, ["position"])
Mbump = bump_particles.mass.sum()
Nbump = len(bump_particles)
print("Nbump=", len(bump_particles), Mbump, Rbump, Nbump)
print("Mass =", Mstar, Mdisk,
disk.mass.sum().in_(units.MSun),
disk.mass.sum() / Mstar)
bump = new_plummer_gas_model(Nbump,
convert_nbody=nbody_system.nbody_to_si(
0.1 * Mbump, Rbump))
a_bump = a_bump | units.AU
bump.x += a_bump
r_bump = a_bump
inner_particles = disk.select(
lambda r: (center_of_mass - r).length() < a_bump, ["position"])
M_inner = inner_particles.mass.sum() + Mstar
v_circ = (constants.G * M_inner *
(2. / r_bump - 1. / a_bump)).sqrt().value_in(units.kms)
bump.velocity += [0, v_circ, 0] | units.kms
print("MM=", M_inner, v_circ)
disk.add_particles(bump)
disk.h_smooth = Rmin / (Ndisk + Nbump)
star = Particles(1)
star.mass = Mstar
star.radius = 1. | units.RSun
star.position = [0, 0, 0] | units.AU
star.velocity = [0, 0, 0] | units.kms
# star2=Particles(1)
# star2.mass=Mstar
# star2.radius=1. | units.RSun
# star2.position = [1, 0, 0] | units.AU
# star2.velocity = [0, 30, 0] | units.kms
hydro = Fi(converter)
# hydror = Fi(channel_type="ibis", hostname="galgewater")
hydro.parameters.use_hydro_flag = True
hydro.parameters.radiation_flag = False
hydro.parameters.self_gravity_flag = True
hydro.parameters.gamma = 1.
hydro.parameters.isothermal_flag = True
hydro.parameters.integrate_entropy_flag = False
hydro.parameters.timestep = 0.125 | units.yr
hydro.gas_particles.add_particles(disk)
gravity = Hermite(converter)
gravity.particles.add_particles(star)
# gravity.particles.add_particles(star2)
# gravity.particles.move_to_center()
channel_from_gravity_to_framework = gravity.particles.new_channel_to(star)
channel_from_hydro_to_framework = hydro.particles.new_channel_to(disk)
# make a repository of the star+disk particles in moving bodies
# moving_bodies = star.union(disk)
moving_bodies = ParticlesSuperset([star, disk])
moving_bodies.move_to_center()
write_set_to_file(moving_bodies, filename, 'hdf5')
gravity_hydro = bridge.Bridge(use_threading=False)
gravity_hydro.add_system(gravity, (hydro, ))
gravity_hydro.add_system(hydro, (gravity, ))
Etot_init = gravity_hydro.kinetic_energy + gravity_hydro.potential_energy
Etot_prev = Etot_init
time = 0.0 | t_end.unit
dt = t_end / float(n_steps)
gravity_hydro.timestep = dt / 10.
while time < t_end:
time += dt
gravity_hydro.evolve_model(time)
Etot_prev_se = gravity_hydro.kinetic_energy + gravity_hydro.potential_energy
channel_from_gravity_to_framework.copy()
channel_from_hydro_to_framework.copy()
write_set_to_file(moving_bodies, filename, 'hdf5')
Ekin = gravity_hydro.kinetic_energy
Epot = gravity_hydro.potential_energy
Etot = Ekin + Epot
print("T=", time, end=' ')
print("E= ", Etot, "Q= ", Ekin / Epot, end=' ')
print("dE=", (Etot_init - Etot) / Etot, "ddE=",
(Etot_prev - Etot) / Etot)
print("star=", star)
Etot_prev = Etot
gravity_hydro.stop()
def main(Mstar=1, Ndisk=100, Mdisk= 0.001, Rmin=1, Rmax=100, t_end=10, n_steps=10, filename="nbody.hdf5"):
# numpy.random.seed(111)
Mstar = Mstar | units.MSun
Mdisk = Mdisk | units.MSun
Rmin = Rmin | units.AU
Rmax = Rmax | units.AU
t_end = t_end | units.yr
# converter=nbody_system.nbody_to_si(Mdisk, Rmax)
converter=nbody_system.nbody_to_si(Mstar, Rmin)
disk = ProtoPlanetaryDisk(Ndisk, convert_nbody=converter, densitypower=1.5,
Rmin=Rmin.value_in(units.AU),
Rmax=Rmax.value_in(units.AU),q_out=1.0,
discfraction=1.0).result
disk.move_to_center()
center_of_mass = disk.center_of_mass()
print center_of_mass
a_bump = 50
Rbump = 10 | units.AU
bump_location = center_of_mass + ([0, a_bump, 0] | units.AU)
bump_particles = disk.select(lambda r: (center_of_mass-r).length()<Rbump,["position"])
Mbump =bump_particles.mass.sum()
Nbump = len(bump_particles)
print "Nbump=", len(bump_particles), Mbump, Rbump, Nbump
print "Mass =", Mstar, Mdisk, disk.mass.sum().in_(units.MSun), disk.mass.sum()/Mstar
bump = new_plummer_gas_model(Nbump, convert_nbody=nbody_system.nbody_to_si(0.1*Mbump, Rbump))
a_bump = a_bump | units.AU
bump.x += a_bump
r_bump = a_bump
inner_particles = disk.select(lambda r: (center_of_mass-r).length()<a_bump,["position"])
M_inner = inner_particles.mass.sum() + Mstar
v_circ = (constants.G*M_inner*(2./r_bump - 1./a_bump)).sqrt().value_in(units.kms)
bump.velocity += [0, v_circ, 0] | units.kms
print "MM=", M_inner, v_circ
disk.add_particles(bump)
disk.h_smooth= Rmin/(Ndisk+Nbump)
star=Particles(1)
star.mass=Mstar
star.radius=1. | units.RSun
star.position = [0, 0, 0] | units.AU
star.velocity = [0, 0, 0] | units.kms
# star2=Particles(1)
# star2.mass=Mstar
# star2.radius=1. | units.RSun
# star2.position = [1, 0, 0] | units.AU
# star2.velocity = [0, 30, 0] | units.kms
hydro=Fi(converter)
# hydror = Fi(channel_type="ibis", hostname="galgewater")
hydro.parameters.use_hydro_flag=True
hydro.parameters.radiation_flag=False
hydro.parameters.self_gravity_flag=True
hydro.parameters.gamma=1.
hydro.parameters.isothermal_flag=True
hydro.parameters.integrate_entropy_flag=False
hydro.parameters.timestep=0.125 | units.yr
hydro.gas_particles.add_particles(disk)
gravity = Hermite(converter)
gravity.particles.add_particles(star)
# gravity.particles.add_particles(star2)
# gravity.particles.move_to_center()
channel_from_gravity_to_framework = gravity.particles.new_channel_to(star)
channel_from_hydro_to_framework = hydro.particles.new_channel_to(disk)
# make a repository of the star+disk particles in moving bodies
# moving_bodies = star.union(disk)
moving_bodies = ParticlesSuperset([star, disk])
moving_bodies.move_to_center()
write_set_to_file(moving_bodies, filename, 'hdf5')
gravity_hydro = bridge.Bridge(use_threading=False)
gravity_hydro.add_system(gravity, (hydro,) )
gravity_hydro.add_system(hydro, (gravity,) )
Etot_init = gravity_hydro.kinetic_energy + gravity_hydro.potential_energy
Etot_prev = Etot_init
time = 0.0 | t_end.unit
dt = t_end/float(n_steps)
gravity_hydro.timestep = dt/10.
while time < t_end:
time += dt
gravity_hydro.evolve_model(time)
Etot_prev_se = gravity_hydro.kinetic_energy + gravity_hydro.potential_energy
channel_from_gravity_to_framework.copy()
channel_from_hydro_to_framework.copy()
write_set_to_file(moving_bodies, filename, 'hdf5')
Ekin = gravity_hydro.kinetic_energy
Epot = gravity_hydro.potential_energy
Etot = Ekin + Epot
print "T=", time,
print "E= ", Etot, "Q= ", Ekin/Epot,
print "dE=", (Etot_init-Etot)/Etot, "ddE=", (Etot_prev-Etot)/Etot
print "star=", star
Etot_prev = Etot
gravity_hydro.stop()
def main(Mstar = 1|units.MSun,
Ndisk=100, Mdisk=0.9|units.MSun,
Rmin=1.0|units.AU, Rmax=100.0|units.AU,
Mbump=0.1|units.MSun,Rbump=10.0|units.AU, abump=10|units.AU,
t_end=1, n_steps=10):
converter=nbody_system.nbody_to_si(Mdisk, Rmin)
from amuse.ext.protodisk import ProtoPlanetaryDisk
bodies = ProtoPlanetaryDisk(Ndisk, convert_nbody=converter,
densitypower=1.5, Rmin=1.0,
Rmax=Rmax/Rmin, q_out=1.0,
discfraction=1.0).result
Mdisk = bodies.mass.sum()
bodies.move_to_center()
com = bodies.center_of_mass()
mm = Mdisk/float(Ndisk)
Nbump = Mbump/mm
bump = new_plummer_gas_model(Nbump, convert_nbody=nbody_system.nbody_to_si(Mbump, Rbump))
bump.x += abump
r_bump = abump
inner_particles = bodies.select(lambda r: (com-r).length()<abump,["position"])
M_inner = inner_particles.mass.sum() + Mstar
v_circ = (constants.G*M_inner*(2./r_bump - 1./abump)).sqrt().value_in(units.kms)
bump.velocity += [0, v_circ, 0] | units.kms
bodies.add_particles(bump)
star=Particles(1)
star.mass=Mstar
star.radius= Rmin
star.position = [0, 0, 0] | units.AU
star.velocity = [0, 0, 0] | units.kms
import math
P_bump = (abump**3*4*math.pi**2/(constants.G*(Mbump+Mstar))).sqrt()
t_end *= P_bump
hydro = Gadget2(converter)
hydro.gas_particles.add_particles(bodies)
hydro.dm_particles.add_particles(star)
Etot_init = hydro.kinetic_energy + hydro.potential_energy + hydro.thermal_energy
particles = ParticlesSuperset([star, bodies])
particles.move_to_center()
particles.new_channel_to(hydro.particles).copy()
bodies.h_smooth = Rmin # for the plotting routine
channel_to_star = hydro.dm_particles.new_channel_to(star)
channel_to_bodies = hydro.gas_particles.new_channel_to(bodies)
write_set_to_file(star, "stars.hdf5","hdf5")
write_set_to_file(bodies, "hydro.hdf5","hdf5")
time = 0.0 | t_end.unit
dt = t_end/float(n_steps)
while time < t_end:
time += dt
hydro.evolve_model(time)
channel_to_star.copy()
channel_to_bodies.copy()
write_set_to_file(star, "stars.hdf5","hdf5")
write_set_to_file(bodies, "hydro.hdf5","hdf5")
star.radius = Rmin
from hydro_sink_particles import hydro_sink_particles
lost = hydro_sink_particles(star, bodies)
if len(lost)>0:
hydro.particles.remove_particles(lost)
hydro.particles.synchronize_to(particles)
print "Disk=", hydro.model_time, len(bodies), len(lost), lost.mass.sum(), star.mass
Ekin = hydro.kinetic_energy
Epot = hydro.potential_energy
Eth = hydro.thermal_energy
Etot = Ekin + Epot + Eth
print "T=", hydro.get_time(), "M=", hydro.gas_particles.mass.sum(),
print "E= ", Etot, "Q= ", (Ekin+Eth)/Epot, "dE=", (Etot_init-Etot)/Etot
print "Star=", hydro.model_time, star[0].mass, star[0].position
hydro.stop()