kappa

dust_emissivity.dust.kappa(nu, nu0=<Quantity 271.1 GHz>, kappa0=<Quantity 0.0114 cm2 / g>, beta=1.75)

Compute the opacity $kappa$ given a reference frequency (or wavelength) and a power law governing the opacity as a fuction of frequency:

$$ kappa = kappa_0 left(frac{nu}{nu_0}right)^{beta} $$

Parameters:

nu: astropy.Quantity [u.spectral() equivalent]

The frequency at which to evaluate kappa

nu0: astropy.Quantity [u.spectral() equivalent]

The reference frequency at which $kappa$ is defined

kappa0: astropy.Quantity [cm^2/g]

The dust opacity per gram of H2 along the line of sight. Because of the H2 conversion, this factor implicitly includes a dust to gas ratio (usually assumed 100)

beta: float

The power-law index governing kappa as a function of nu