On the maximum value of the cosmic abundance of oxygen and the oxygen yield |
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| Authors: | Leonid S Pilyugin Trinh X Thuan José M Vílchez |
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| Institution: | Main Astronomical Observatory of National Academy of Sciences of Ukraine, 27 Zabolotnogo str., 03680 Kiev, Ukraine;Astronomy Department, University of Virginia, PO Box 400325, Charlottesville, VA 22904, USA;Instituto de Astrofísica de Andalucía, CSIC, Apdo 3004, 18080 Granada, Spain |
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| Abstract: | We search for the maximum oxygen abundance in spiral galaxies. Because this maximum value is expected to occur in the centres of the most luminous galaxies, we have constructed the luminosity – central metallicity diagram for spiral galaxies, based on a large compilation of existing data on oxygen abundances of H ii regions in spiral galaxies. We found that this diagram shows a plateau at high luminosities (?22.3 ? M B ??20.3) , with a constant maximum value of the gas-phase oxygen abundance 12 + log (O/H) ～ 8.87 . This provides strong evidence that the oxygen abundance in the centres of the most luminous metal-rich galaxies reaches the maximum attainable value of oxygen abundance. Since some fraction of the oxygen (about 0.08 dex) is expected to be locked into dust grains, the maximum value of the true gas + dust oxygen abundance in spiral galaxies is 12 + log(O/H) ～ 8.95. This value is a factor of ～2 higher than the recently estimated solar value. Based on the derived maximum oxygen abundance in galaxies, we found the oxygen yield to be about 0.0035, depending on the fraction of oxygen incorporated into dust grains. |
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| Keywords: | ISM: abundances H ii regions galaxies: abundances |
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