Impacts of Chemical Abundances on Modeling Photoionization Case of Hydrogen and Helium
American Journal of Astronomy and Astrophysics
Volume 5, Issue 5, September 2017, Pages: 50-56
Received: Sep. 25, 2017; Accepted: Oct. 30, 2017; Published: Jan. 19, 2018
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Belay Sitotaw Goshu, Department of Physics, College of Natural and Computational Science, Dire Dawa University, Dire Dawa, Ethiopia
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A number of models were utilized to study hydrogen and helium ionization structure by assessing the impacts of effective temperatures by different scholars. But this work mainly focused on two temperatures, 35 000 K and 45 000 K and enhancement of abundances. Each model is characterized based on the solar abundances and enhanced abundances by scale factors of 5. The photoionization code cloudy was used to construct the model of the nebulae. The result revealed that at high temperature 45 000 K, the sphere of helium close to hydrogen whereas at low temperature 35 000 K, hydrogen ion ratio is more dominant than helium and its radius is greater than it. Moreover, the chemical abundances ratio at each stage of ionization depends oneffective temperatures and enhancement of abundances.
Photoionization, Chemical Abundances, Nebulae, Enhancement
To cite this article
Belay Sitotaw Goshu, Impacts of Chemical Abundances on Modeling Photoionization Case of Hydrogen and Helium, American Journal of Astronomy and Astrophysics. Vol. 5, No. 5, 2017, pp. 50-56. doi: 10.11648/j.ajaa.20170505.11
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Ferland G. J., et al., 2013, Hazy, Introduction to cloudy c13.04.
Osterbrock, D. E. 1989, Astrophysics of gaseous nebulae and active galactic nuclei, University Science Books, 1989.
Grevesse N and Sauval A. J. Standard Solar Composition. Space Science Reviews, 85:161-174, May 1998. doi: 10.1023/A:1005161325181.
Asplund M., Grevesse N., Sauval A. J. and Scott P., 2009, ARRA, 47, 481.
Morisset C., 2017, Planetary Nebulae: Multi-wavelength probes of stellar and galactic evolution, International Astronomical Union Proceedings IAU Symposium No. 323, 2017.
Bohigas J., 2008, The Astrophysical Journal, 674, 95-975.
Pilyugin L. S., Ve’lchez J. M., and Thuan T. X, 2010, The Astro- physical Journal, 720: 1738-1751.
Tielens A. G. G. M., The physics and the chemistry of the interstellar medium, 2005, Cambridge university press, pp 240.
Holweger H., Photospheric Abundances: Problems, Updates, Implications. In R. F. Wimmer-Schweingruber, editor, Joint SOHO/ACE workshop\Solar and Galactic Composition", volume 598 of American Institute of Physics Conference Series, page 23, 2001. doi: 10.1063/1.1433974.
Allende Prieto C., Lambert D. L., and Asplund M., the Forbidden Abundance of Oxygen in the Sun. ApJ, 556: L63-L66, July 2001. doi: 10.1086/322874.
Allende Prieto C., Lambert D. L. and Asplund M., A Reappraisal of the Solar Photospheric C/O Ratio. ApJ, 573: L137-L140, July 2002. doi: 10.1086/342095.
Zsarg’o J., D. J. Hillier D. J., and Georgiev L. N., RevMexAA (Seriede Conferencias), 33, 58-58 (2008).
Kinkel U and Rosa M. R., 1994, Astron. Astrophys, 282, L37-L40.
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