MSCE  Vol.3 No.4 , April 2015
Photoionization Modelling of H II Region for Oxygen Ions
ABSTRACT
We present phoionization model calculations of ionization fraction of hydrogen, helium and oxy-gen at low density of photoionized nebulae using the photoionization code CLOUDY. The ionization parameter is between -2.0 ≤ log(U) ≤ 1.0, and we study them by changing the abundances of oxy-gen from -2.5 ≤ log(O/H) ≤ -5.0. This was tested first by Campbell (1988) [1]. But, this was differ-ent in highest abundances of oxygen, filling factor and carbon abundances. We change the abun-dances of carbon by 0.5 dex of solar value, to avoid formation CO in the process. We include the charge transfer interaction between oxygen ions and hydrogen atom. Based on this process, we have calculated the ionization profiles of O0, O+, O2+ O3+ and O4+ in the presence and absence of charge exchange between hydrogen and oxygen. In this work, we assumed the effective rate of co-efficient for the charge transfer is the order of ≈10-9 cm-3-s-1.

Cite this paper
Goshu, S. and Smits, D. (2015) Photoionization Modelling of H II Region for Oxygen Ions. Journal of Materials Science and Chemical Engineering, 3, 7-16. doi: 10.4236/msce.2015.34002.
References
[1]   Campbell, A. (1988) Physical Conditions in H II Galaxies.

[2]   Osterbrock, D.E. (1989) Astrophysics of Gaseous Nebulae and Active Galactic Nuclei.

[3]   Ferland, G.J. (2011) Hazy: Introduction to Cloudy c10.00.

[4]   Grevesse, N. (1989) Solar System Abundances of the Elements. AIP Conference Proceedings No. 183: Cosmic Abundances of Matter.

[5]   Stasinska, G. (2002) Abundance Determinant Ions in HII Regions and Planetary Nebulae.

[6]   Stromgren, B. (1939) Stromgren Sphere. Astrophysical Journal, 89, 526.

[7]   Field, G.B. and Steigman, G. (1971) Charge Transfer and Ionization Equilibrium in the Interstellar Medium. Astrophysical Journal, 166, 59.
http://dx.doi.org/10.1086/150941

[8]   Steigman, G. (1975) Charge Transfer Reactions in Multiple Charged Ion-Atom Collisions Astrophysics. Astrophysical Journal, 199, 642-646.
http://dx.doi.org/10.1086/153732

 
 
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