Dust Depletion

The dust_depletion parameter controls how we model the depletion of metals on to dust grains in the chemistry solver. The possible options are described below.

Dust Depletion Model Description
None
The dust-to-gas ratio, is scaled linearly with the metallicity, i.e. we
assume a constant dust-to-metals ratio. However, the abundances of metals
in the gas phase are not reduced to account for the depletion of metals
on to dust grains.
J09
The depletion of individual metals on to dust grains is calculated from
the observationally measured depletion factors (i.e. the fraction of each
element that is in dust) in the Milky Way from Jenkins (2009). These are
expressed as functions of a parameter F_star, which represents the overal
strength of dust depletion and is itself a function of density,
n_Htot. We also impose an upper temperature cut of 1e6 K, above which
all metals are put in the gas phase, to account for the destruction of
dust grains due to sputtering at high gas temperatures. The total dust-
to-gas ratio is then calculated by summing over the depletions of each
individual element. The dust abundances and depletion factors are thus
functions of gas temperature, density and metallicity. See Richings et
al. (in prep) for details of how we implement this model in CHIMES.
DC16
As J09, but using the updated fit parameters from De Cia et al. (2016)
for the individual element depletion factors, where available. For
elements that are not included in De Cia et al. (2016), we use the fits
from Jenkins (2009). See Richings et al. (in prep) for details.
Colibre
The dust-to-gas ratio and depletion factors of individual elements are
calculated as in the COLIBRE model. See Ploeckinger & Schaye (2020) for
details.