CNO via pynucastro

We can redo the same integration but using pynucastro to manage the integration. This will allow us to make pretty pictures.

import numpy as np
import matplotlib.pyplot as plt
import pynucastro as pyna

net = pyna.network_helper(["p", "he4",
                           "c12", "c13",
                           "n13", "n14", "n15",
                           "o14", "o15", "o16", "o17", "o18",
                           "f17", "f18", "f19",
                           "ne18", "ne19", "ne20"], tabular_ordering=["ffn", "oda"])

We’ll setup the same initial conditions

rho = 150
T = 1.5e7

comp = pyna.Composition(net.unique_nuclei)
comp.X[pyna.Nucleus("p")] = 0.7
comp.X[pyna.Nucleus("he4")] = 0.28
comp.X[pyna.Nucleus("c12")] = 0.02

Y0 = comp.get_molar_array()

Now we can integrate

tmax = 1.e20

sol = net.integrate_network(tmax, rho, T, Y0, atol=1.e-8)

/opt/hostedtoolcache/Python/3.14.5/x64/lib/python3.14/site-packages/pynucastro/rates/derived_rate.py:125: UserWarning: C12 partition function is not supported by tables: set log_pf = 0.0 by default
  warnings.warn(UserWarning(f'{nuc} partition function is not supported by tables: set log_pf = 0.0 by default'))
/opt/hostedtoolcache/Python/3.14.5/x64/lib/python3.14/site-packages/pynucastro/rates/derived_rate.py:125: UserWarning: N13 partition function is not supported by tables: set log_pf = 0.0 by default
  warnings.warn(UserWarning(f'{nuc} partition function is not supported by tables: set log_pf = 0.0 by default'))
/opt/hostedtoolcache/Python/3.14.5/x64/lib/python3.14/site-packages/pynucastro/rates/derived_rate.py:125: UserWarning: C13 partition function is not supported by tables: set log_pf = 0.0 by default
  warnings.warn(UserWarning(f'{nuc} partition function is not supported by tables: set log_pf = 0.0 by default'))
/opt/hostedtoolcache/Python/3.14.5/x64/lib/python3.14/site-packages/pynucastro/rates/derived_rate.py:125: UserWarning: N14 partition function is not supported by tables: set log_pf = 0.0 by default
  warnings.warn(UserWarning(f'{nuc} partition function is not supported by tables: set log_pf = 0.0 by default'))
/opt/hostedtoolcache/Python/3.14.5/x64/lib/python3.14/site-packages/pynucastro/rates/derived_rate.py:125: UserWarning: N15 partition function is not supported by tables: set log_pf = 0.0 by default
  warnings.warn(UserWarning(f'{nuc} partition function is not supported by tables: set log_pf = 0.0 by default'))

sol.success

True

Now we can plot the mass fractions.

fig = sol.plot_evolution(ymin=1.e-8)

/opt/hostedtoolcache/Python/3.14.5/x64/lib/python3.14/site-packages/pynucastro/networks/python_network.py:412: UserWarning: Attempt to set non-positive xlim on a log-scaled axis will be ignored.
  ax.set_xlim(tmin, tmax)

We can also look at the flow through the network

X_final = sol.X[:, -1]
comp_final = pyna.Composition(net.unique_nuclei)
comp_final.set_array(X_final)

fig = net.plot(rho, T, comp_final,
               size=(800, 800),
               use_net_rate=True, color_nodes_by_abundance=True)

/opt/hostedtoolcache/Python/3.14.5/x64/lib/python3.14/site-packages/pynucastro/rates/derived_rate.py:125: UserWarning: C12 partition function is not supported by tables: set log_pf = 0.0 by default
  warnings.warn(UserWarning(f'{nuc} partition function is not supported by tables: set log_pf = 0.0 by default'))
/opt/hostedtoolcache/Python/3.14.5/x64/lib/python3.14/site-packages/pynucastro/rates/derived_rate.py:125: UserWarning: N13 partition function is not supported by tables: set log_pf = 0.0 by default
  warnings.warn(UserWarning(f'{nuc} partition function is not supported by tables: set log_pf = 0.0 by default'))
/opt/hostedtoolcache/Python/3.14.5/x64/lib/python3.14/site-packages/pynucastro/rates/derived_rate.py:125: UserWarning: C13 partition function is not supported by tables: set log_pf = 0.0 by default
  warnings.warn(UserWarning(f'{nuc} partition function is not supported by tables: set log_pf = 0.0 by default'))
/opt/hostedtoolcache/Python/3.14.5/x64/lib/python3.14/site-packages/pynucastro/rates/derived_rate.py:125: UserWarning: N14 partition function is not supported by tables: set log_pf = 0.0 by default
  warnings.warn(UserWarning(f'{nuc} partition function is not supported by tables: set log_pf = 0.0 by default'))
/opt/hostedtoolcache/Python/3.14.5/x64/lib/python3.14/site-packages/pynucastro/rates/derived_rate.py:125: UserWarning: N15 partition function is not supported by tables: set log_pf = 0.0 by default
  warnings.warn(UserWarning(f'{nuc} partition function is not supported by tables: set log_pf = 0.0 by default'))