Das Institut für Physik, Institutsbereich Geophysik, Astrophysik und Meteorologie, lädt zu folgendem Vortrag im Rahmen des Astrophysikalischen Kolloquiums ein:
"What is the emission line spectrum of H II regions telling us? Tracing the chemical composition of ISM in the Milky Way.”
Dr. Karla Ziboney Arellano-Córdova
Instituto de Astrofísica de Canarias (IAC)
La Laguna, Tenerife, Spain
The emission line spectrum of H II regions provides information about the chemical composition of the present-day interstellar medium. The study of H II regions as a function of their galactocentric distances in disc galaxies helps to understand and constrain chemical evolution models. In this talk, I will briefly discuss the analysis of the chemical composition of a sample of Galactic H II regions with high and intermediate resolution spectra and some specific problems related to chemical abundance determinations. To do so, we use a sample of 33 spectra, most of them observed with the GTC and VLT telescopes, to study the physical conditions and chemical abundances of different elements: O, N, Ne, S, Cl, Ar and C. We show the radial abundance gradients of those elements using new values of the Galactocentric distances calculated using Gaia DR2 data for some objects. The abundance gradients are compared with previous results of the literature of H II regions and young stars for some elements. Finally, to analyze the enrichment of each element, we compare the Ne/O, S/O, Cl/O and Ar/O abundance ratios as a function of metallicity. We find, that those abundance ratios are constant with metallicity showing mean abundance values close to the Solar abundances for this sample of objects.
Zeit: Mittwoch, 20. November 2019 um 11:45 Uhr s.t.
Ort: Seminarraum 05.11 (1. Stock), Universitätsplatz 5, 8010 Graz