**Table 2:** Fractional abundances of H₂O, CH₃OH, and Si/SiO assumed for the icy mantles and the grain cores.
Species	Abundances [ $\chi$ ]
	Mantles	Cores
H₂O	$7.25 \times 10^{-5}$ ^a	$\ldots$
CH₃OH	${\sim}10^{-6}$ ^b	$\ldots$
Si/SiO	${\sim}10^{-8}$ ^b	${\sim}3.6\times 10^{-5}$ ^c

^a From Whittet & Duley (1991). ^b From Jiménez-Serra et al. (2005).
^c From Anders & Grevesse (1989) and Snow & Witt (1996).

Source LaTeX | All tables | In the text