AAS 204th Meeting, June 2004
Session 61 Structures in the Interstellar Medium
Poster, Wednesday, June 2, 2004, 10:00am-7:00pm, Ballroom

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[61.03] A Complete Helium Model in Cloudy

R. L. Porter, R. P. Bauman, K. B. MacAdam, G. J. Ferland (University of Kentucky)

We summarize the features of the Helium model in the plasma simulation code Cloudy. The model is fast and efficient, and any number of atomic levels may be considered. A complete set of astrophysically relevant processes - including photoionization, continuum pumping, destruction by background opacities, scattering, collisional processes, etc. - is treated self-consistently with the ionization and thermal structure of the surrounding nebula. This self-consistency replaces the need for a number of free parameters in a simpler stand-alone model. These advances will allow the He I spectrum to be understood in a more accurate manner. Applications include precision measurements of the primordial helium abundance and the use of the He I spectrum to determine physical conditions within a nebula. We include an error analysis and an example application.

The author(s) of this abstract have provided an email address for comments about the abstract: rporter@pa.uky.edu

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