A detailed study of the HII region M43 and its ionizing star. I. (S. Simon-Diaz et al.)

Vol. 530In section 6. Interstellar and circumstellar matter

A detailed study of the HII region M43 and its ionizing star. I. Stellar parameters and nebular empirical analysis

by S. Simon-Diaz, J. Garcia-Rojas, C. Esteban, G. Stasinska, A.R. Lopez-Sanchez, and C. Morisset, A&A 530, A57

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Determination of abundance in ionized environments, such as H II regions and planetary nebulae, has long been hampered by the problem of passing from the abundance of the observed ions to that of the element. This is often addressed by a correction factor that takes into account the unmeasured species as a function of temperature and density. This multiaperture spectroscopic study of the prototypical H II region, the central part of the M 43 nebula associated with the Orion nebula, provides a benchmark study of such analyses: the abundance of individual ions comprising the whole of those states spanned by each element have been directly measured without the need for corrections. Important details, the effects of diffuse emission (scattered light from the imbedded stars), dust, and variations in the physical conditions within the ionized gas are included.