Show simple item record

dc.creatorSteigman, Gary
dc.creatorViegas, Sueli M.
dc.creatorGruenwald, Ruth
dc.date.accessioned2011-03-09T19:37:10Z
dc.date.available2011-03-09T19:37:10Z
dc.date.issued1997-11-20
dc.identifier.citationGary Steigman, Sueli M. Viegas, and Ruth Gruenwald, "Temperature Fluctuations and Abundances in H II Galaxies," The Astrophysical Journal 490, no. 1 (1997), doi:10.1086/512790en_US
dc.identifier.issn1538-4357
dc.identifier.urihttp://hdl.handle.net/1811/48223
dc.description.abstractThere is evidence for temperature fluctuations in planetary nebulae and in some Galactic H II regions. If such fluctuations occur in the low-metallicity, extragalactic H II regions used to probe the primordial helium abundance, the derived ^4He mass fraction, Y_P, could be systematically different from the true primordial value. For cooler, mainly high-metallicity H II regions, the derived helium abundance may be nearly unchanged, but the oxygen abundance could have been seriously underestimated. For hotter, mainly low-metallicity H II regions, the oxygen abundance is likely accurate, but the helium abundance could be underestimated. The net effect is to tilt the Y-versus-Z relation, making it flatter and resulting in a higher inferred Y_P. Although this effect could be large, there are no data that allow us to estimate the size of the temperature fluctuations for the extragalactic H II regions. Therefore, we have explored this effect via Monte Carlo simulations of the data in which the abundances derived from a fiducial data set are modified by ΔT chosen from a distribution with 0 ≤ ΔT ≤ ΔT_max, where ΔT_max is varied from 500 to 4000 K. It is interesting that, although this effect shifts the locations of the H II regions in the Y-versus-O/H plane, it does not introduce any significant additional dispersion.en_US
dc.language.isoen_USen_US
dc.publisherAmerican Astronomical Societyen_US
dc.subjectISM: abundancesen_US
dc.subjectH II regionsen_US
dc.subjectgalaxies: ISMen_US
dc.titleTemperature Fluctuations and Abundances in H II Galaxiesen_US
dc.typeArticleen_US
dc.identifier.doi10.1086/512790
dc.identifier.osuauthorsteigman.1


Files in this item

Thumbnail

Items in Knowledge Bank are protected by copyright, with all rights reserved, unless otherwise indicated.

This item appears in the following Collection(s)

Show simple item record