CCM89¶

class dust_extinction.parameter_averages.CCM89(*args, meta=None, name=None, **kwargs)[source]

Bases: BaseExtRvModel

Cardelli, Clayton, & Mathis (1989) Milky Way R(V) dependent model

Parameters:
Rv: float

R(V) = A(V)/E(B-V) = total-to-selective extinction

Raises:
InputParameterError

Input Rv values outside of defined range

Notes

From Cardelli, Clayton, and Mathis (1989, ApJ, 345, 245)

Example showing CCM89 curves for a range of R(V) values.

import numpy as np
import matplotlib.pyplot as plt
import astropy.units as u

from dust_extinction.parameter_averages import CCM89

fig, ax = plt.subplots()

# generate the curves and plot them
x = np.arange(0.5,10.0,0.1)/u.micron

Rvs = ['2.0','3.0','4.0','5.0','6.0']
for cur_Rv in Rvs:
ext_model = CCM89(Rv=cur_Rv)
ax.plot(x,ext_model(x),label='R(V) = ' + str(cur_Rv))

ax.set_xlabel(r'$x$ [$\mu m^{-1}$]')
ax.set_ylabel(r'$A(x)/A(V)$')

ax.legend(loc='best')
plt.show()


Attributes Summary

Methods Summary

 evaluate(in_x, Rv) CCM89 function

Attributes Documentation

Rv_range = [2.0, 6.0]
x_range = [0.3, 10.0]

Methods Documentation

static evaluate(in_x, Rv)[source]

CCM89 function

Parameters:
in_x: float

expects either x in units of wavelengths or frequency or assumes wavelengths in wavenumbers [1/micron]

internally wavenumbers are used

Returns:
axav: np array (float)

A(x)/A(V) extinction curve [mag]

Raises:
ValueError

Input x values outside of defined range