Complex molecule formation in grain mantles | Astronomy & Astrophysics (A&A)

Free Access

Table 4:

Gas/Surface model - fixed parameters.
Parameter	Value	Ref.
UV Radiation field	$3.0 \times 10 ^{8}$ cm^-2 s^-1 Hz^-1	1
Cosmic ray ionization rate	$1.3 \times 10^{-17}$ s^-1	2
Grain albedo	0.5	3
Sticking coefficient	1.0	4
Sticking coefficient for hydrogen atoms	0.3	5
Yield per UV photon on grain mantle impact	10^-6	6
Surface density of sites	$1.5 \times 10^{15}$ cm^-2	4
Number of sites per grain	10⁶	4
Fractional density of grains (w.r.t. Density of H)	$1.33 \times 10^{-12}$	4
Average grain radius	10^-5 cm	4
Barrier width between adjacent sites	10^-8 cm	4
Grain velocity (non-thermal)	10⁴ cm s^-1	7

References. (1) Draine (1978); (2) van Dishoeck & Black (1986); (3) Whittet (1992); (4) Hasegawa et al. (1992); (5) Brown (1988); (6) Willacy (1993); (7) V $\stackrel{..}{\rm o}$ lk et al. (1980).

Source LaTeX | All tables | In the text

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.