barak.abundances.calc_abund¶
- barak.abundances.calc_abund(X, Y, logNX, logNY)[source]¶
Find the abundance relative to solar given two elements and their column densities.
Parameters : X, Y : str
Element identifiers (for example ‘C’, ‘Si’, ‘Mg’).
logNX : array_like, shape (N,)
log10 of element X column density in cm^-2.
logNY : array_like, shape (N,)
log10 of element Y column density in cm^-2.
Returns : abundance_ratio : ndarray, shape (N,)
Abundance ratio relative to solar, [X/Y].
Notes
The abundance ratio is defined:
[X/Y] = log10 (n_X / n_Y) - log10 (n_Xsun / n_Ysun)
Where N_Xsun / N_Ysun is the ratio of the number density of species X to species Y for ‘proto-solar’ abundances (See Lodders 2003, ApJ, 591, 1220). For example, if [X/Y] = 0, it has the same abundance as the proto-solar values. If [X/Y] = 1, then ten times larger, [X/Y] = -1, then ten times smaller.
If Y is hydrogen, then this estimates the metallicity.