Young Magnetic Models – A Brief Exploration

Preliminary comparison of magnetic stellar models against non-magnetic, standard stellar models.


In [1]:
%matplotlib inline
import matplotlib.pyplot as plt
from scipy.interpolate import interp1d
import numpy as np

Magnetic isochrones were computed earlier. Details can be found in this notebook entry on a small magnetic stellar grid. I'll focus on those computed with the Grevesse, Asplund, & Sauval (2007; henceforth GAS07) solar abundance distribution. Three ages will be examined: 5 Myr, 12 Myr, and 30 Myr, in line with the previous magnetic model diagnostic figures.


In [2]:
std_iso_05 = np.genfromtxt('files/dmestar_00005.0myr_z+0.00_a+0.00_gas07_t010.iso')
std_iso_12 = np.genfromtxt('files/dmestar_00012.0myr_z+0.00_a+0.00_gas07_t010.iso')
std_iso_30 = np.genfromtxt('files/dmestar_00030.0myr_z+0.00_a+0.00_gas07_t010.iso')

In [3]:
mag_iso_05 = np.genfromtxt('files/dmestar_00005.0myr_gas07_z+0.00_a+0.00_mag25kG.iso')
mag_iso_12 = np.genfromtxt('files/dmestar_00012.0myr_gas07_z+0.00_a+0.00_mag25kG.iso')
mag_iso_30 = np.genfromtxt('files/dmestar_00030.0myr_gas07_z+0.00_a+0.00_mag25kG.iso')

Examining, first, the mass-radius, mass-Teff, and mass-luminosity relationships as a function of age.


In [4]:
fig, ax = plt.subplots(3, 1, figsize=(8, 12), sharex=True)

ax[2].set_xlabel('Mass ($M_{\\odot}$)', fontsize=20.)
ax[0].set_ylabel('Radius ($R_{\\odot}$)', fontsize=20.)
ax[1].set_ylabel('Temperature (K)', fontsize=20.)
ax[2].set_ylabel('Luminosity ($L_{\\odot}$)', fontsize=20.)
for axis in ax:
    axis.tick_params(which='major', axis='both', length=10., labelsize=16.)

# Standard model Mass-Radius
ax[0].plot(std_iso_05[:, 0], 10**std_iso_05[:, 4], '-',  lw=2, color='#555555')
ax[0].plot(std_iso_12[:, 0], 10**std_iso_12[:, 4], '-',  lw=2, color='#1e90ff')
ax[0].plot(std_iso_30[:, 0], 10**std_iso_30[:, 4], '-',  lw=2, color='#800000')

# Magnetic model Mass-Radius
ax[0].plot(mag_iso_05[:, 0], 10**mag_iso_05[:, 4], '--', lw=2, color='#555555', dashes=(20.,10.))
ax[0].plot(mag_iso_12[:, 0], 10**mag_iso_12[:, 4], '--', lw=2, color='#1e90ff', dashes=(20.,10.))
ax[0].plot(mag_iso_30[:, 0], 10**mag_iso_30[:, 4], '--', lw=2, color='#800000', dashes=(20.,10.))

# Standard model Mass-Teff
ax[1].plot(std_iso_05[:, 0], 10**std_iso_05[:, 1], '-',  lw=2, color='#555555')
ax[1].plot(std_iso_12[:, 0], 10**std_iso_12[:, 1], '-',  lw=2, color='#1e90ff')
ax[1].plot(std_iso_30[:, 0], 10**std_iso_30[:, 1], '-',  lw=2, color='#800000')

# Magnetic model Mass-Teff
ax[1].plot(mag_iso_05[:, 0], 10**mag_iso_05[:, 1], '--', lw=2, color='#555555', dashes=(20.,10.))
ax[1].plot(mag_iso_12[:, 0], 10**mag_iso_12[:, 1], '--', lw=2, color='#1e90ff', dashes=(20.,10.))
ax[1].plot(mag_iso_30[:, 0], 10**mag_iso_30[:, 1], '--', lw=2, color='#800000', dashes=(20.,10.))

# Standard model Mass-Luminosity
ax[2].plot(std_iso_05[:, 0], 10**std_iso_05[:, 3], '-',  lw=2, color='#555555')
ax[2].plot(std_iso_12[:, 0], 10**std_iso_12[:, 3], '-',  lw=2, color='#1e90ff')
ax[2].plot(std_iso_30[:, 0], 10**std_iso_30[:, 3], '-',  lw=2, color='#800000')

# Magnetic model Mass-Luminosity
ax[2].plot(mag_iso_05[:, 0], 10**mag_iso_05[:, 3], '--', lw=2, color='#555555', dashes=(20.,10.))
ax[2].plot(mag_iso_12[:, 0], 10**mag_iso_12[:, 3], '--', lw=2, color='#1e90ff', dashes=(20.,10.))
ax[2].plot(mag_iso_30[:, 0], 10**mag_iso_30[:, 3], '--', lw=2, color='#800000', dashes=(20.,10.))

fig.tight_layout()


Note that, in the figure above, standard stellar evolution models are shown as solid lines and magnetic stellar evolution models as dashed lines. Ages are indicated by color: grey = 5 Myr, blue = 12 Myr, red = 30 Myr.

HR Diagram comparison:


In [5]:
fig, ax = plt.subplots(1, 1, figsize=(8.0, 8.0))

ax.set_xlabel('Effective Temperature (K)', fontsize=20.)
ax.set_ylabel('$\\log_{10} (L / L_{\\odot})$', fontsize=20.)
ax.set_xlim(5000., 2500.)
ax.tick_params(which='major', axis='both', length=10., labelsize=16.)

# Standard models
ax.plot(10**std_iso_05[:, 1], std_iso_05[:, 3], '-',  lw=2, color='#555555')
ax.plot(10**std_iso_12[:, 1], std_iso_12[:, 3], '-',  lw=2, color='#1e90ff')
ax.plot(10**std_iso_30[:, 1], std_iso_30[:, 3], '-',  lw=2, color='#800000')

# Magnetic models
ax.plot(10**mag_iso_05[:, 1], mag_iso_05[:, 3], '--', lw=2, color='#555555', dashes=(20.,10.))
ax.plot(10**mag_iso_12[:, 1], mag_iso_12[:, 3], '--', lw=2, color='#1e90ff', dashes=(20.,10.))
ax.plot(10**mag_iso_30[:, 1], mag_iso_30[:, 3], '--', lw=2, color='#800000', dashes=(20.,10.))


Out[5]:
[<matplotlib.lines.Line2D at 0x119b452d0>]

Line styles and colors represent the same model combinations, as before.

Lithium abundance as a function of mass, temperature, and luminosity:


In [6]:
fig, ax = plt.subplots(1, 3, figsize=(15, 5), sharey=True)

ax[0].set_xlabel('Mass ($M_{\\odot}$)', fontsize=20.)
ax[1].set_xlabel('Temperature (K)', fontsize=20.)
ax[2].set_xlabel('$\\log_{10}(L/L_{\\odot})$', fontsize=20.)
ax[0].set_ylabel('A(Li)', fontsize=20.)
for axis in ax:
    axis.set_ylim(1.5, 3.5)
    axis.tick_params(which='major', axis='both', length=10., labelsize=16.)

# x-axis limits
ax[0].set_xlim(1.0, 0.1)
ax[1].set_xlim(4500., 2500.)
ax[2].set_xlim(0.0, -2.5)

# Standard model Mass-A(Li)
ax[0].plot(std_iso_05[:, 0], std_iso_05[:, 5], '-',  lw=2, color='#555555')
ax[0].plot(std_iso_12[:, 0], std_iso_12[:, 5], '-',  lw=2, color='#1e90ff')
ax[0].plot(std_iso_30[:, 0], std_iso_30[:, 5], '-',  lw=2, color='#800000')

# Magnetic model Mass-A(Li)
ax[0].plot(mag_iso_05[:, 0], mag_iso_05[:, 5], '--', lw=2, color='#555555', dashes=(20.,10.))
ax[0].plot(mag_iso_12[:, 0], mag_iso_12[:, 5], '--', lw=2, color='#1e90ff', dashes=(20.,10.))
ax[0].plot(mag_iso_30[:, 0], mag_iso_30[:, 5], '--', lw=2, color='#800000', dashes=(20.,10.))

# Standard model Teff-A(Li)
ax[1].plot(10**std_iso_05[:, 1], std_iso_05[:, 5], '-',  lw=2, color='#555555')
ax[1].plot(10**std_iso_12[:, 1], std_iso_12[:, 5], '-',  lw=2, color='#1e90ff')
ax[1].plot(10**std_iso_30[:, 1], std_iso_30[:, 5], '-',  lw=2, color='#800000')

# Magnetic model Teff-A(Li)
ax[1].plot(10**mag_iso_05[:, 1], mag_iso_05[:, 5], '--', lw=2, color='#555555', dashes=(20.,10.))
ax[1].plot(10**mag_iso_12[:, 1], mag_iso_12[:, 5], '--', lw=2, color='#1e90ff', dashes=(20.,10.))
ax[1].plot(10**mag_iso_30[:, 1], mag_iso_30[:, 5], '--', lw=2, color='#800000', dashes=(20.,10.))

# Standard model Luminosity-A(Li)
ax[2].plot(std_iso_05[:, 3], std_iso_05[:, 5], '-',  lw=2, color='#555555')
ax[2].plot(std_iso_12[:, 3], std_iso_12[:, 5], '-',  lw=2, color='#1e90ff')
ax[2].plot(std_iso_30[:, 3], std_iso_30[:, 5], '-',  lw=2, color='#800000')

# Magnetic model Luminosity-A(Li)
ax[2].plot(mag_iso_05[:, 3], mag_iso_05[:, 5], '--', lw=2, color='#555555', dashes=(20.,10.))
ax[2].plot(mag_iso_12[:, 3], mag_iso_12[:, 5], '--', lw=2, color='#1e90ff', dashes=(20.,10.))
ax[2].plot(mag_iso_30[:, 3], mag_iso_30[:, 5], '--', lw=2, color='#800000', dashes=(20.,10.))

fig.tight_layout()



In [ ]: