http://arxiv.org/abs/1905.10159
We present preliminary results of the study of the radial distribution of helium in the Milky Way. We use 37 spectra from 23 Galactic HII regions observed with VLT, GTC and Magellan Telescope. Using PyNeb, we calculate the abundance of He$^+$ with all the He$\thinspace$I detected lines. In most cases, both the average abundance of He$^+$ and its associated dispersion are higher when triplet lines are used. Although corrections for collisional processes are considered in the calculations, the differences in the He$^+$ abundance are not negligible between both spin configurations. This suggests that self-absorption processes are important in most triplet lines. Four ICFs were used to estimate the contribution of He$^0$ in the total abundance. The resulting radial distribution of helium has a negative slope when singlet lines are used, regardless of the ICF used.
J. Méndez-Delgado, C. Esteban and J. García-Rojas
Mon, 27 May 19
16/51
Comments: 5 pages, 4 figures. Poster presented in the II workshop on Chemical Abundances in Gaseous Nebulae, held between 11-14 March 2019 in Sao Jose dos Campos, Sao Paulo, Brazil
You must be logged in to post a comment.