Reduction of chemical network: fractional ionization in protoplanetary disks

This web page contains supplementary data to the article D.A. Semenov, D.S. Wiebe, & Th. Henning "Reduction of chemical networks. II. Fractional ionisation in protoplanetary discs" (2004), A&A, 417, 93. It include all those reduced networks that are cited in this paper along with the "full" network and two files with the physical conditions and initial abundances. The "full" network is based on the UMIST95 database of chemical reactions and can be downloaded here.

As initial abundances, we adopted a set of molecular abundances computed for the conditions typical of dark molecular clouds (T=10 K, nH=2000 cm-3, t=106 yrs) starting from the "low metal" abundances of Lee et al. (1996). This file can be found here.

We used the 1+1D disk model of P. D'Alessio et al. (1999) as a guide for the physical conditions thought to be encountered in T Tau protoplanetary disks. The disk is divided by 7 vertical and 11 radial grid slices. Then, we estimated temperature (T ), density (r ), intensity of the stellar (G0) and interstellar UV radiation, extinction factors in vertical (AVIS) and radial (AVSt) directions as well as X-ray (zX) and cosmic ray (zCR) ionization rates in all these 77 disk grid points. The corresponding files for 7 vertical slices can be downloaded here:

1) r= 1 AU: 1environ.inp.Z_1

2) r= 3 AU: 1environ.inp.Z_2

3) r= 10 AU: 1environ.inp.Z_3

4) r= 30 AU: 1environ.inp.Z_4

5) r=100 AU: 1environ.inp.Z_5

6) r=300 AU: 1environ.inp.Z_6

7) r=370 AU: 1environ.inp.Z_7

Finally, for each considered disk point, we isolated a reduced chemical network which governs the fractional ionization with better than 100% accuracy for the entire evolutionary time span 0.001 yrs<t<106 yrs. All these reduced networks can be found in the following table:

Amount of species and reactions in each reduced network
ri/zi,j 0 1 2 3 4 5 6 7 8 9 10
1 AU 5x3 58x142 39x78 30x58 26x105 26x105 28x166 26x70 5x5 5x5 5x5
3 AU 13x14 60x102 62x142 62x218 115x308 20x85 19x77 39x173 31x84 17x46 17x46
10 AU 94x246 94x246 113x364 29x88 29x88 18x52 18x52 19x77 18x52 18x52 18x52
30 AU 18x40 18x40 18x40 18x40 18x40 19x77 17x46 17x46 17x46 17x46 17x46
100 AU 19x40 19x40 19x40 19x40 64x204 19x77 19x77 19x77 19x77 19x77 19x77
300 AU 19x40 19x40 19x40 19x40 96x407 19x77 25x170 19x77 19x77 19x77 19x77
370 AU 19x40 19x40 19x40 19x40 95x399 19x77 19x77 19x77 19x77 19x77 19x77

In addition to the individual reduced network, we combined from them a SIngle REduced Network for the whole disk (SIREN). This network includes 113 species involved in 518 reactions and allows to compute disk fractional ionization with reasonable accuracy of less than 100% for entire 1 Myr evolutionary time span and all disk locations but inner disk midplane. It can be downloaded here. The ratio between fractional ionizations computed with SIREN and "full" networks for t=106 yrs is presented below:

Note that all forementioned reduced networks are valid for the specified disk model and initial abundances!

Created: 05 November 2003 by Dmitry A. Semenov