def setup_stellar_evolution_model():
out_pickle_file = os.path.join(get_path_to_results(),
"super_giant_stellar_structure.pkl")
if os.path.exists(out_pickle_file):
return out_pickle_file
stellar_evolution = MESA(redirection="none")
stars = Particles(1)
stars.mass = 10.0 | units.MSun
stellar_evolution.initialize_module_with_default_parameters()
stellar_evolution.particles.add_particles(stars)
stellar_evolution.commit_particles()
print "Evolving a MESA star with mass:", stellar_evolution.particles[
0].mass
try:
while True:
stellar_evolution.evolve_model()
except AmuseException as ex:
print "Evolved star to", stellar_evolution.particles[0].age
print "Radius:", stellar_evolution.particles[0].radius
pickle_stellar_model(stellar_evolution.particles[0], out_pickle_file)
stellar_evolution.stop()
return out_pickle_file
def setup_stellar_evolution_model():
out_pickle_file = os.path.join(get_path_to_results(), "super_giant_stellar_structure.pkl")
if os.path.exists(out_pickle_file):
return out_pickle_file
stellar_evolution = MESA(redirection="none")
stars = Particles(1)
stars.mass = 10.0 | units.MSun
stellar_evolution.particles.add_particles(stars)
"""
print "Evolving a MESA star with mass:", stellar_evolution.particles[0].mass
try:
while True:
stellar_evolution.evolve_model()
except AmuseException as ex:
print "Evolved star to t=", stellar_evolution.particles[0].age,
print "Mass:", stellar_evolution.particles[0].mass
print "Radius:", stellar_evolution.particles[0].radius
print "core-mass:", stellar_evolution.particles[0].core_mass
"""
while stellar_evolution.particles[0].stellar_type <= 12 | units.stellar_type:
stellar_evolution.evolve_model()
pickle_stellar_model(stellar_evolution.particles[0], out_pickle_file)
stellar_evolution.stop()
return out_pickle_file
def brunt_vaisala_frequency_squared_profile(mass, age):
stellar_evolution = MESA()
star = stellar_evolution.particles.add_particle(Particle(mass=mass))
star.evolve_for(age)
radius_profile = star.get_radius_profile()
brunt_profile = star.get_brunt_vaisala_frequency_squared_profile()
stellar_evolution.stop()
return radius_profile.as_quantity_in(units.RSun), brunt_profile
def brunt_vaisala_frequency_squared_profile(mass, age):
stellar_evolution = MESA()
star = stellar_evolution.particles.add_particle(Particle(mass=mass))
star.evolve_for(age)
radius_profile = star.get_radius_profile()
brunt_profile = star.get_brunt_vaisala_frequency_squared_profile()
stellar_evolution.stop()
return radius_profile.as_quantity_in(units.RSun), brunt_profile
def mesa(self, number_of_stars):
result = MESA()
result.initialize_code()
if number_of_stars > (10):
warnings.warn("You're simulating a large number of stars with MESA. This may not be such a good idea...")
if number_of_stars > (1000):
raise Exception("You want to simulate with more than 1000 stars using MESA, this is not supported")
return result
def main():
temperatures_original = [] | units.K
luminosities_original = [] | units.LSun
temperatures_helium = [] | units.K
luminosities_helium = [] | units.LSun
star = Particle()
star.mass = 12.0 | units.MSun
stop_radius = 100 | units.RSun
stellar_evolution = MESA()
se_star = stellar_evolution.particles.add_particle(star)
print("Evolving a", star.mass, "star with",
stellar_evolution.__class__.__name__, end=' ')
print("until its radius exceeds", stop_radius)
while (se_star.radius < stop_radius):
se_star.evolve_one_step()
temperatures_original.append(se_star.temperature)
luminosities_original.append(se_star.luminosity)
###BOOKLISTSTART1###
number_of_zones = se_star.get_number_of_zones()
composition = se_star.get_chemical_abundance_profiles()
index = (composition[0] > 1.0e-9).nonzero()[0][0] # first zone with X > 1.0e-9
print("Creating helium star, from the inner", index,
"(out of", str(number_of_zones)+") shells.")
helium_star = stellar_evolution.new_particle_from_model(dict(
mass = (se_star.get_cumulative_mass_profile() * se_star.mass)[:index],
radius = se_star.get_radius_profile()[:index],
rho = se_star.get_density_profile()[:index],
temperature = se_star.get_temperature_profile()[:index],
luminosity = se_star.get_luminosity_profile()[:index],
X_H = composition[0][:index],
X_He = composition[1][:index] + composition[2][:index],
X_C = composition[3][:index],
X_N = composition[4][:index],
X_O = composition[5][:index],
X_Ne = composition[6][:index],
X_Mg = composition[7][:index],
X_Si = composition[7][:index]*0.0,
X_Fe = composition[7][:index]*0.0), 0.0 | units.Myr)
###BOOKLISTSTOP1###
print("\nStar properties before helium star evolution:\n",
stellar_evolution.particles)
for i in range(1000):
helium_star.evolve_one_step()
temperatures_helium.append(helium_star.temperature)
luminosities_helium.append(helium_star.luminosity)
print("\nStar properties after helium star evolution:\n",
stellar_evolution.particles)
stellar_evolution.stop()
return temperatures_original, luminosities_original, \
temperatures_helium, luminosities_helium
def main():
temperatures_original = [] | units.K
luminosities_original = [] | units.LSun
temperatures_helium = [] | units.K
luminosities_helium = [] | units.LSun
star = Particle()
star.mass = 12.0 | units.MSun
stop_radius = 100 | units.RSun
stellar_evolution = MESA()
se_star = stellar_evolution.particles.add_particle(star)
print("Evolving a", star.mass, "star with",
stellar_evolution.__class__.__name__, end=' ')
print("until its radius exceeds", stop_radius)
while (se_star.radius < stop_radius):
se_star.evolve_one_step()
temperatures_original.append(se_star.temperature)
luminosities_original.append(se_star.luminosity)
###BOOKLISTSTART1###
number_of_zones = se_star.get_number_of_zones()
composition = se_star.get_chemical_abundance_profiles()
index = (composition[0] > 1.0e-9).nonzero()[0][0] # first zone with X > 1.0e-9
print("Creating helium star, from the inner", index,
"(out of", str(number_of_zones)+") shells.")
helium_star = stellar_evolution.new_particle_from_model(dict(
mass = (se_star.get_cumulative_mass_profile() * se_star.mass)[:index],
radius = se_star.get_radius_profile()[:index],
rho = se_star.get_density_profile()[:index],
temperature = se_star.get_temperature_profile()[:index],
luminosity = se_star.get_luminosity_profile()[:index],
X_H = composition[0][:index],
X_He = composition[1][:index] + composition[2][:index],
X_C = composition[3][:index],
X_N = composition[4][:index],
X_O = composition[5][:index],
X_Ne = composition[6][:index],
X_Mg = composition[7][:index],
X_Si = composition[7][:index]*0.0,
X_Fe = composition[7][:index]*0.0), 0.0 | units.Myr)
###BOOKLISTSTOP1###
print("\nStar properties before helium star evolution:\n",
stellar_evolution.particles)
for i in range(1000):
helium_star.evolve_one_step()
temperatures_helium.append(helium_star.temperature)
luminosities_helium.append(helium_star.luminosity)
print("\nStar properties after helium star evolution:\n",
stellar_evolution.particles)
stellar_evolution.stop()
return temperatures_original, luminosities_original, \
temperatures_helium, luminosities_helium
def mesa(self, number_of_stars):
result = MESA()
result.initialize_code()
if number_of_stars > (10):
warnings.warn(
"You're simulating a large number of stars with MESA. This may not be such a good idea...")
if number_of_stars > (1000):
raise Exception(
"You want to simulate with more than 1000 stars using MESA, this is not supported")
return result
def setup_stellar_evolution_model():
out_pickle_file = os.path.join(
get_path_to_results(), "super_giant_stellar_structure.pkl")
if os.path.exists(out_pickle_file):
return out_pickle_file
stellar_evolution = MESA(redirection="none")
stars = Particles(1)
stars.mass = 10.0 | units.MSun
stellar_evolution.initialize_module_with_default_parameters()
stellar_evolution.particles.add_particles(stars)
stellar_evolution.commit_particles()
print(
"Evolving a MESA star with mass:",
stellar_evolution.particles[0].mass
)
try:
while True:
stellar_evolution.evolve_model()
except AmuseException as ex:
print "Evolved star to", stellar_evolution.particles[0].age
print "Radius:", stellar_evolution.particles[0].radius
pickle_stellar_model(stellar_evolution.particles[0], out_pickle_file)
stellar_evolution.stop()
return out_pickle_file
def code_factory(self):
try:
MESA()
except Exception as message:
self.skip(
"Tried to instantiate a new object of the optional code with type '{0}', but this code is not available"
.format(MESA))
return MESA
def setup_stellar_evolution_model():
out_pickle_file = os.path.join(get_path_to_results(),
"super_giant_stellar_structure.pkl")
if os.path.exists(out_pickle_file):
return out_pickle_file
print "Creating initial conditions from a MESA stellar evolution model..."
stellar_evolution = MESA(redirection = "none")
stars = Particles(1)
stars.mass = 10.0 | units.MSun
stellar_evolution.particles.add_particles(stars)
while stellar_evolution.particles[0].stellar_type <= 12|units.stellar_type:
stellar_evolution.evolve_model()
pickle_stellar_model(stellar_evolution.particles[0], out_pickle_file)
stellar_evolution.stop()
return out_pickle_file
def setup_stellar_evolution_model():
out_pickle_file = os.path.join(get_path_to_results(), "super_giant_stellar_structure.pkl")
if os.path.exists(out_pickle_file):
return out_pickle_file
stellar_evolution = MESA(redirection = "none")
stars = Particles(1)
stars.mass = 10.0 | units.MSun
stellar_evolution.particles.add_particles(stars)
"""
print "Evolving a MESA star with mass:", stellar_evolution.particles[0].mass
try:
while True:
stellar_evolution.evolve_model()
except AmuseException as ex:
print "Evolved star to t=", stellar_evolution.particles[0].age,
print "Mass:", stellar_evolution.particles[0].mass
print "Radius:", stellar_evolution.particles[0].radius
print "core-mass:", stellar_evolution.particles[0].core_mass
"""
while stellar_evolution.particles[0].stellar_type <= 12|units.stellar_type:
stellar_evolution.evolve_model()
# while stellar_evolution.particles[0].stellar_type <= 3|units.stellar_type:
# stellar_evolution.evolve_model()
pickle_stellar_model(stellar_evolution.particles[0], out_pickle_file)
stellar_evolution.stop()
return out_pickle_file
def slowtest3(self):
print "Testing ParallelStellarEvolution evolve_model"
particles = Particles(4)
particles.mass = range(1, 1 + len(particles)) | units.MSun
serial = MESA()
inserial = serial.particles.add_particles(particles)
self.assertAlmostEqual(inserial.mass,
range(1, 1 + len(particles)) | units.MSun)
serial.evolve_model(0.2 | units.Myr)
parallel = ParallelStellarEvolution(MESA,
number_of_workers=3,
**default_options)
inparallel = parallel.particles.add_particles(particles)
self.assertAlmostEqual(inparallel.mass,
range(1, 1 + len(particles)) | units.MSun)
parallel.evolve_model(0.2 | units.Myr)
self.assertEqual(parallel.model_time, 0.2 | units.Myr)
self.assertTrue(numpy.all(inparallel.age >= (0.2 | units.Myr)))
self.assertTrue(
numpy.all(
inparallel.age - inparallel.time_step <= (0.2 | units.Myr)))
self.assertEqual(inserial.luminosity, inparallel.luminosity)
self.assertEqual(inserial.time_step, inparallel.time_step)
self.assertEqual(inserial.temperature, inparallel.temperature)
serial.stop()
parallel.stop()
def slowtest3(self):
print "Testing ParallelStellarEvolution evolve_model"
particles = Particles(4)
particles.mass = range(1, 1+len(particles)) | units.MSun
serial = MESA()
inserial = serial.particles.add_particles(particles)
self.assertAlmostEqual(inserial.mass, range(1, 1+len(particles)) | units.MSun)
serial.evolve_model(0.2 | units.Myr)
parallel = ParallelStellarEvolution(MESA, number_of_workers=3, **default_options)
inparallel = parallel.particles.add_particles(particles)
self.assertAlmostEqual(inparallel.mass, range(1, 1+len(particles)) | units.MSun)
parallel.evolve_model(0.2 | units.Myr)
self.assertEqual(parallel.model_time, 0.2 | units.Myr)
self.assertTrue(numpy.all(inparallel.age >= (0.2 | units.Myr)))
self.assertTrue(numpy.all(inparallel.age - inparallel.time_step <= (0.2 | units.Myr)))
self.assertEqual(inserial.luminosity, inparallel.luminosity)
self.assertEqual(inserial.time_step, inparallel.time_step)
self.assertEqual(inserial.temperature, inparallel.temperature)
serial.stop()
parallel.stop()
def simulate_evolution_tracks(
masses=[0.5, 1.0, 1.25, 1.5, 2.25, 3.0, 5.0, 9.0, 15.0] | units.MSun):
stellar_evolution = MESA()
stellar_evolution.parameters.AGB_wind_scheme = 0
stellar_evolution.parameters.RGB_wind_scheme = 0
stars = datamodel.Particles(len(masses), mass=masses)
stars = stellar_evolution.pre_ms_stars.add_particles(stars)
data = {}
for star in stars:
luminosity = [] | units.LSun
temperature = [] | units.K
time = [] | units.yr
print('Evolving pre main sequence star with')
print(' mass:', star.mass)
print(' luminosity:', star.luminosity)
print(' radius:', star.radius)
while star.stellar_type == 17 | units.stellar_type:
luminosity.append(star.luminosity)
temperature.append(star.temperature)
time.append(star.age)
star.evolve_one_step()
print('Evolved pre main sequence star to:', star.stellar_type)
print(' age:', star.age)
print(' mass:', star.mass)
print(' luminosity:', star.luminosity)
print(' radius:', star.radius)
print()
stardata = {}
stardata['luminosity'] = luminosity
stardata['temperature'] = temperature
stardata['time'] = time
data[star.mass] = stardata
return data
def evolve_star_and_apply_mass_loss(radius, mdot):
print("Evolve to radius = ", radius, "and then apply mdot =", mdot)
stev = MESA(redirection='none')
# We have to switch off all wind mass loss for manual mass loss to work
stev.parameters.AGB_wind_scheme = 0
stev.parameters.RGB_wind_scheme = 0
star = stev.particles.add_particle(Particle(mass=2 | units.MSun))
while star.radius < radius:
star.evolve_one_step()
print("evolved to:", star.age, "->", star.radius)
star1 = star.copy()
# High mass loss rates can only be calculated for small time steps
star.time_step = 1. | units.yr
star.mass_change = mdot
print(star.mass_change)
star.evolve_one_step()
print_report(star1, star, mdot)
def setup_stellar_evolution_model():
out_pickle_file = os.path.join(get_path_to_results(),
"super_giant_stellar_structure.pkl")
if os.path.exists(out_pickle_file):
return out_pickle_file
print("Creating initial conditions from a MESA stellar evolution model...")
stellar_evolution = MESA(redirection="none")
stars = Particles(1)
stars.mass = 10.0 | units.MSun
stellar_evolution.particles.add_particles(stars)
while stellar_evolution.particles[
0].stellar_type <= 12 | units.stellar_type:
stellar_evolution.evolve_model()
pickle_stellar_model(stellar_evolution.particles[0], out_pickle_file)
stellar_evolution.stop()
return out_pickle_file
def head_on_stellar_merger(
masses=[0.3, 3.0] | units.MSun,
star_age=310.0 | units.Myr,
initial_separation=4.0 | units.RSun,
angle=numpy.pi / 3,
initial_speed=3000.0 | units.km / units.s,
initial_speed_perpendicular=30.0 | units.km / units.s,
number_of_sph_particles=50000,
t_end=1.0e4 | units.s,
sph_code=Fi,
):
"""
masses: Mass of the two stars
star_age: Initial age of the stars
number_of_sph_particles: Total number of particles of both stars, divided
according to their masses
t_end: (Physical, not computational) duration of the hydrodynamics
simulation
sph_code: Code to use for the hydrodynamics simulation
"""
# Convert some of the input parameters to string, for use in output file
# names:
n_string = "n" + ("%1.0e" % (number_of_sph_particles)
).replace("+0", "").replace("+", "")
t_end_string = "t" + ("%1.0e" % (t_end.value_in(units.s))
).replace("+0", "").replace("+", "")
base_output_file_name = os.path.join(
get_path_to_results(), "stellar_merger_"+n_string+"_"+t_end_string)
stars = Particles(2)
stars.mass = masses
try:
stellar_evolution = MESA()
stellar_evolution.initialize_code()
except:
print "MESA was not built. Returning."
return
stellar_evolution.commit_parameters()
stellar_evolution.particles.add_particles(stars)
stellar_evolution.commit_particles()
print "Evolving stars with MESA..."
stellar_evolution.evolve_model(star_age)
number_of_sph_particles_1 = int(
round(
number_of_sph_particles
* (
stellar_evolution.particles[0].mass
/ stellar_evolution.particles.mass.sum()
)
)
)
number_of_sph_particles_2 = (
number_of_sph_particles - number_of_sph_particles_1
)
print "Creating initial conditions from a MESA stellar evolution model:"
print(
stellar_evolution.particles[0].mass,
"star consisting of", number_of_sph_particles_1, "particles."
)
sph_particles_1 = convert_stellar_model_to_SPH(
stellar_evolution.particles[0],
number_of_sph_particles_1,
seed=12345
).gas_particles
print(
stellar_evolution.particles[1].mass,
"star consisting of", number_of_sph_particles_2, "particles."
)
sph_particles_2 = convert_stellar_model_to_SPH(
stellar_evolution.particles[1],
number_of_sph_particles_2
).gas_particles
initial_separation += stellar_evolution.particles.radius.sum()
sph_particles_2.x += numpy.cos(angle) * initial_separation
sph_particles_2.y += numpy.sin(angle) * initial_separation
sph_particles_1.vx += numpy.cos(angle) * initial_speed - \
numpy.sin(angle) * initial_speed_perpendicular
sph_particles_1.vy += numpy.cos(angle) * initial_speed_perpendicular + \
numpy.sin(angle) * initial_speed
view = [-0.5, 0.5, -0.5, 0.5] * \
(initial_separation + stellar_evolution.particles.radius.sum())
stellar_evolution.stop()
all_sph_particles = ParticlesSuperset([sph_particles_1, sph_particles_2])
all_sph_particles.move_to_center()
unit_converter = ConvertBetweenGenericAndSiUnits(
1.0 | units.RSun, constants.G, t_end)
hydro_legacy_code = sph_code(unit_converter)
n_steps = 100
hydro_legacy_code.parameters.n_smooth = 96
try:
hydro_legacy_code.parameters.timestep = t_end / n_steps
except Exception as exc:
if "parameter is read-only" not in str(exc):
raise
hydro_legacy_code.gas_particles.add_particles(all_sph_particles)
print "Evolving to t =", t_end, " (using", sph_code.__name__, "SPH code)."
for time, i_step in [(i*t_end/n_steps, i) for i in range(1, n_steps+1)]:
hydro_legacy_code.evolve_model(time)
if not i_step % 4:
hydro_plot(
view,
hydro_legacy_code,
(300, 300),
base_output_file_name +
"_hydro_image{0:=03}.png".format(i_step)
)
hydro_legacy_code.stop()
print "All done!\n"
def head_on_stellar_merger(
masses = [0.3, 3.0] | units.MSun,
star_age = 310.0 | units.Myr,
maximally_evolved_stars = False,
initial_separation = 4.0 | units.RSun,
angle = numpy.pi / 3,
initial_speed = 3000.0 | units.km / units.s,
initial_speed_perpendicular = 30.0 | units.km / units.s,
number_of_sph_particles = 1000,
t_end = 1.0e4 | units.s,
sph_code = Fi,
steps_per_snapshot = 4,
snapshot_size = 100,
use_stored_stellar_models = True
):
"""
masses: Mass of the two stars
star_age: Initial age of the stars (if maximally_evolved_stars is False)
maximally_evolved_stars: Evolve stars as far as the Stellar Evolution code can get
number_of_sph_particles: Total number of particles of both stars, divided according to their masses
t_end: (Physical, not computational) duration of the hydrodynamics simulation
sph_code: Code to use for the hydrodynamics simulation
steps_per_snapshot: A hydroplot snapshot is generated each time after this many steps (0 or None means no snapshots)
snapshot_size: Size of the snapshot in pixels along one dimension
use_stored_stellar_models: Flag to use previously stored stellar model files (for speed-up).
"""
# Convert some of the input parameters to string, for use in output file names:
n_string = "n" + ("%1.0e"%(number_of_sph_particles)).replace("+0","").replace("+","")
t_end_string = "t" + ("%1.0e"%(t_end.value_in(units.s))).replace("+0","").replace("+","")
masses_string = ("m1_" + ("%0.3e"%(masses[0].value_in(units.MSun))).replace("+0","").replace("+","") +
"_m2_" + ("%0.3e"%(masses[1].value_in(units.MSun))).replace("+0","").replace("+",""))
if maximally_evolved_stars:
star_age_string = "a_max"
else:
star_age_string = "a" + ("%0.3e"%(star_age.value_in(units.Myr))).replace("+0","").replace("+","")
base_output_file_name = os.path.join(get_path_to_results(), "stellar_merger_"+n_string+"_"+t_end_string)
pickle_file_1 = os.path.join(get_path_to_results(), "stellar_merger_"+masses_string+"_"+star_age_string+"_1.pkl")
pickle_file_2 = os.path.join(get_path_to_results(), "stellar_merger_"+masses_string+"_"+star_age_string+"_2.pkl")
if not use_stored_stellar_models or not (os.path.exists(pickle_file_1) and os.path.exists(pickle_file_2)):
stars = Particles(2)
stars.mass = masses
try:
stellar_evolution = MESA()
stellar_evolution.initialize_code()
except:
print "MESA was not built. Returning."
return
stellar_evolution.commit_parameters()
stellar_evolution.particles.add_particles(stars)
stellar_evolution.commit_particles()
if maximally_evolved_stars:
try:
while True:
stellar_evolution.evolve_model()
except AmuseException as exception:
print exception
else:
stellar_evolution.evolve_model(star_age)
if os.path.exists(pickle_file_1):
print "Could not save stellar model 1: file already exists."
else:
pickle_stellar_model(stellar_evolution.particles[0], pickle_file_1)
print "Stellar model 1 saved at:", pickle_file_1
if os.path.exists(pickle_file_2):
print "Could not save stellar model 2: file already exists."
else:
pickle_stellar_model(stellar_evolution.particles[1], pickle_file_2)
print "Stellar model 2 saved at:", pickle_file_2
stellar_evolution.stop()
model_1 = StellarModel2SPH(None, None, pickle_file = pickle_file_1)
model_2 = StellarModel2SPH(None, None, pickle_file = pickle_file_2)
model_1.unpickle_stellar_structure()
model_2.unpickle_stellar_structure()
composition = model_2.composition_profile
midpoints = model_2.midpoints_profile[1:-1]
specific_internal_energy = model_2.specific_internal_energy_profile
number_of_sph_particles_1 = int(round(number_of_sph_particles *
(model_1.mass / (model_1.mass + model_2.mass))))
number_of_sph_particles_2 = number_of_sph_particles - number_of_sph_particles_1
print "Creating initial conditions from a MESA stellar evolution model:"
print model_1.mass, "star consisting of", number_of_sph_particles_1, "particles."
sph_particles_1 = convert_stellar_model_to_SPH(
None,
number_of_sph_particles_1,
seed=12345,
pickle_file = pickle_file_1
).gas_particles
print model_2.mass, "star consisting of", number_of_sph_particles_2, "particles."
sph_particles_2 = convert_stellar_model_to_SPH(
None,
number_of_sph_particles_2,
pickle_file = pickle_file_2
).gas_particles
initial_separation += model_1.radius + model_2.radius
sph_particles_2.x += numpy.cos(angle) * initial_separation
sph_particles_2.y += numpy.sin(angle) * initial_separation
sph_particles_1.vx += numpy.cos(angle) * initial_speed - numpy.sin(angle) * initial_speed_perpendicular
sph_particles_1.vy += numpy.cos(angle) * initial_speed_perpendicular + numpy.sin(angle) * initial_speed
view = [-0.5, 0.5, -0.5, 0.5] * (initial_separation + model_1.radius + model_2.radius)
all_sph_particles = ParticlesSuperset([sph_particles_1, sph_particles_2])
all_sph_particles.move_to_center()
unit_converter = ConvertBetweenGenericAndSiUnits(1.0 | units.RSun, constants.G, t_end)
hydro_legacy_code = sph_code(unit_converter)
n_steps = 100
hydro_legacy_code.parameters.n_smooth = 96
try:
hydro_legacy_code.parameters.timestep = t_end / n_steps
except Exception as exc:
if not "parameter is read-only" in str(exc): raise
hydro_legacy_code.gas_particles.add_particles(all_sph_particles)
times = [] | units.Myr
kinetic_energies = [] | units.J
potential_energies = [] | units.J
thermal_energies = [] | units.J
print "Evolving to:", t_end
for time, i_step in [(i*t_end/n_steps, i) for i in range(1, n_steps+1)]:
hydro_legacy_code.evolve_model(time)
times.append(time)
kinetic_energies.append( hydro_legacy_code.kinetic_energy)
potential_energies.append( hydro_legacy_code.potential_energy)
thermal_energies.append( hydro_legacy_code.thermal_energy)
if steps_per_snapshot and (not i_step % steps_per_snapshot):
hydro_plot(
view,
hydro_legacy_code,
(snapshot_size, snapshot_size),
base_output_file_name + "_hydro_image{0:=03}.png".format(i_step)
)
hydro_legacy_code.gas_particles.new_channel_to(all_sph_particles).copy_attributes(
['mass', 'x','y','z', 'vx','vy','vz', 'u'])
center_of_mass = all_sph_particles.center_of_mass().as_quantity_in(units.RSun)
center_of_mass_velocity = all_sph_particles.center_of_mass_velocity().as_quantity_in(units.km / units.s)
print
print "center_of_mass:", center_of_mass
print "center_of_mass_velocity:", center_of_mass_velocity
all_sph_particles.position -= center_of_mass
sph_midpoints = all_sph_particles.position.lengths()
energy_plot(
times,
kinetic_energies, potential_energies, thermal_energies,
base_output_file_name+"_energy_evolution.png"
)
thermal_energy_plot(
times,
thermal_energies,
base_output_file_name+"_thermal_energy_evolution.png"
)
composition_comparison_plot(
midpoints, composition[0],
sph_midpoints, all_sph_particles.h1,
base_output_file_name+"_composition_h1.png"
)
internal_energy_comparison_plot(
midpoints, specific_internal_energy,
sph_midpoints, all_sph_particles.u,
base_output_file_name+"_new_u.png"
)
hydro_plot(
[-2.0, 2.0, -2.0, 2.0] | units.RSun,
hydro_legacy_code,
(100, 100),
base_output_file_name + "_hydro_image.png"
)
hydro_legacy_code.stop()
print "All done!\n"
def head_on_stellar_merger(
masses=[0.3, 3.0] | units.MSun,
star_age=310.0 | units.Myr,
maximally_evolved_stars=False,
initial_separation=4.0 | units.RSun,
angle=numpy.pi / 3,
initial_speed=3000.0 | units.km / units.s,
initial_speed_perpendicular=30.0 | units.km / units.s,
number_of_sph_particles=1000,
t_end=1.0e4 | units.s,
sph_code=Fi,
steps_per_snapshot=4,
snapshot_size=100,
use_stored_stellar_models=True
):
"""
masses: Mass of the two stars
star_age: Initial age of the stars (if maximally_evolved_stars is False)
maximally_evolved_stars: Evolve stars as far as the Stellar Evolution code
can get
number_of_sph_particles: Total number of particles of both stars, divided
according to their masses
t_end: (Physical, not computational) duration of the hydrodynamics
simulation
sph_code: Code to use for the hydrodynamics simulation
steps_per_snapshot: A hydroplot snapshot is generated each time after this
many steps (0 or None means no snapshots)
snapshot_size: Size of the snapshot in pixels along one dimension
use_stored_stellar_models: Flag to use previously stored stellar model
files (for speed-up).
"""
# Convert some of the input parameters to string, for use in output file
# names:
n_string = "n" + ("%1.0e" % (number_of_sph_particles)
).replace("+0", "").replace("+", "")
t_end_string = "t" + ("%1.0e" % (t_end.value_in(units.s))
).replace("+0", "").replace("+", "")
masses_string = (
"m1_"
+ (
"%0.3e" % (masses[0].value_in(units.MSun))
).replace("+0", "").replace("+", "")
+ "_m2_"
+ (
"%0.3e" % (masses[1].value_in(units.MSun))
).replace("+0", "").replace("+", "")
)
if maximally_evolved_stars:
star_age_string = "a_max"
else:
star_age_string = "a" + \
("%0.3e" % (star_age.value_in(units.Myr))).replace(
"+0", "").replace("+", "")
base_output_file_name = os.path.join(
get_path_to_results(), "stellar_merger_"+n_string+"_"+t_end_string)
pickle_file_1 = os.path.join(get_path_to_results(
), "stellar_merger_"+masses_string+"_"+star_age_string+"_1.pkl")
pickle_file_2 = os.path.join(get_path_to_results(
), "stellar_merger_"+masses_string+"_"+star_age_string+"_2.pkl")
if not use_stored_stellar_models or not (os.path.exists(pickle_file_1) and os.path.exists(pickle_file_2)):
stars = Particles(2)
stars.mass = masses
try:
stellar_evolution = MESA()
stellar_evolution.initialize_code()
except:
print("MESA was not built. Returning.")
return
stellar_evolution.commit_parameters()
stellar_evolution.particles.add_particles(stars)
stellar_evolution.commit_particles()
if maximally_evolved_stars:
try:
while True:
stellar_evolution.evolve_model()
except AmuseException as exception:
print(exception)
else:
stellar_evolution.evolve_model(star_age)
if os.path.exists(pickle_file_1):
print("Could not save stellar model 1: file already exists.")
else:
pickle_stellar_model(stellar_evolution.particles[0], pickle_file_1)
print("Stellar model 1 saved at:", pickle_file_1)
if os.path.exists(pickle_file_2):
print("Could not save stellar model 2: file already exists.")
else:
pickle_stellar_model(stellar_evolution.particles[1], pickle_file_2)
print("Stellar model 2 saved at:", pickle_file_2)
stellar_evolution.stop()
model_1 = StellarModel2SPH(None, None, pickle_file=pickle_file_1)
model_2 = StellarModel2SPH(None, None, pickle_file=pickle_file_2)
model_1.unpickle_stellar_structure()
model_2.unpickle_stellar_structure()
composition = model_2.composition_profile
midpoints = model_2.midpoints_profile[1:-1]
specific_internal_energy = model_2.specific_internal_energy_profile
number_of_sph_particles_1 = int(
round(
number_of_sph_particles
* (model_1.mass / (model_1.mass + model_2.mass))
)
)
number_of_sph_particles_2 = (
number_of_sph_particles
- number_of_sph_particles_1
)
print("Creating initial conditions from a MESA stellar evolution model:")
print(
model_1.mass,
"star consisting of",
number_of_sph_particles_1,
"particles."
)
sph_particles_1 = convert_stellar_model_to_SPH(
None,
number_of_sph_particles_1,
seed=12345,
pickle_file = pickle_file_1
).gas_particles
print(
model_2.mass,
"star consisting of",
number_of_sph_particles_2,
"particles."
)
sph_particles_2 = convert_stellar_model_to_SPH(
None,
number_of_sph_particles_2,
pickle_file=pickle_file_2
).gas_particles
initial_separation += model_1.radius + model_2.radius
sph_particles_2.x += numpy.cos(angle) * initial_separation
sph_particles_2.y += numpy.sin(angle) * initial_separation
sph_particles_1.vx += (
numpy.cos(angle) * initial_speed
- numpy.sin(angle) * initial_speed_perpendicular
)
sph_particles_1.vy += (
numpy.cos(angle) * initial_speed_perpendicular
+ numpy.sin(angle) * initial_speed
)
view = (
[-0.5, 0.5, -0.5, 0.5]
* (initial_separation + model_1.radius + model_2.radius)
)
all_sph_particles = ParticlesSuperset([sph_particles_1, sph_particles_2])
all_sph_particles.move_to_center()
unit_converter = ConvertBetweenGenericAndSiUnits(
1.0 | units.RSun, constants.G, t_end)
hydro_legacy_code = sph_code(unit_converter)
n_steps = 100
hydro_legacy_code.parameters.n_smooth = 96
try:
hydro_legacy_code.parameters.timestep = t_end / n_steps
except Exception as exc:
if "parameter is read-only" not in str(exc):
raise
hydro_legacy_code.gas_particles.add_particles(all_sph_particles)
times = [] | units.Myr
kinetic_energies = [] | units.J
potential_energies = [] | units.J
thermal_energies = [] | units.J
print("Evolving to:", t_end)
for time, i_step in [(i*t_end/n_steps, i) for i in range(1, n_steps+1)]:
hydro_legacy_code.evolve_model(time)
times.append(time)
kinetic_energies.append(hydro_legacy_code.kinetic_energy)
potential_energies.append(hydro_legacy_code.potential_energy)
thermal_energies.append(hydro_legacy_code.thermal_energy)
if steps_per_snapshot and (not i_step % steps_per_snapshot):
hydro_plot(
view,
hydro_legacy_code,
(snapshot_size, snapshot_size),
base_output_file_name +
"_hydro_image{0:=03}.png".format(i_step)
)
hydro_legacy_code.gas_particles.new_channel_to(
all_sph_particles
).copy_attributes(
['mass', 'x', 'y', 'z', 'vx', 'vy', 'vz', 'u']
)
center_of_mass = all_sph_particles.center_of_mass(
).as_quantity_in(units.RSun)
center_of_mass_velocity = all_sph_particles.center_of_mass_velocity(
).as_quantity_in(units.km / units.s)
print()
print("center_of_mass:", center_of_mass)
print("center_of_mass_velocity:", center_of_mass_velocity)
all_sph_particles.position -= center_of_mass
sph_midpoints = all_sph_particles.position.lengths()
energy_plot(
times,
kinetic_energies, potential_energies, thermal_energies,
base_output_file_name+"_energy_evolution.png"
)
thermal_energy_plot(
times,
thermal_energies,
base_output_file_name+"_thermal_energy_evolution.png"
)
composition_comparison_plot(
midpoints, composition[0],
sph_midpoints, all_sph_particles.h1,
base_output_file_name+"_composition_h1.png"
)
internal_energy_comparison_plot(
midpoints, specific_internal_energy,
sph_midpoints, all_sph_particles.u,
base_output_file_name+"_new_u.png"
)
hydro_plot(
[-2.0, 2.0, -2.0, 2.0] | units.RSun,
hydro_legacy_code,
(100, 100),
base_output_file_name + "_hydro_image.png"
)
hydro_legacy_code.stop()
print("All done!\n")