J. García-Rojas

Neutron-capture Elements in Planetary Nebulae: First Detections of Near-infrared [Te iii] and [Br v] Emission Lines

We have identified two new near-infrared emission lines in the spectra of planetary nebulae (PNe) arising from heavy elements produced by neutron capture reactions: [Te III] 2.1019

Abundances and ADFs in planetary nebulae with [WC] central stars

mu

The abundances of O, N, S, Cl, Ne, Ar, and Fe in H II regions of the Magellanic Clouds

m and [Br V] 1.6429

Radial metallicity gradients with Galactic nebular probes

mu

Neutron-capture element abundances in the planetary nebula NGC 5315 from deep high-resolution optical and near-IR spectrophotometry

m. [Te III] was detected in both NGC 7027 and IC 418, while [Br V] was seen in NGC 7027. The observations were obtained with the medium-resolution spectrograph EMIR on the 10.4m Gran Telescopio Canarias at La Palma, and with the high-resolution spectrograph IGRINS on the 2.7m Harlan J. Smith telescope at McDonald Observatory. New calculations of atomic data for these ions, specifically A-values and collision strengths, are presented and used to derive ionic abundances of Te

Study on the Abundance Discrepancy Problem in the Magellanic Clouds

^{2+}

Ring Nebulae: Tracers of the CNO Nucleosynthesis

and Br

A window on the efficiency of the s-process in AGB stars: chemical abundances of n-capture elements in the planetary nebula NGC 3918

^{4+}

s-process Enrichment in the Planetary Nebula NGC 3918

. We also derive ionic abundances of other neutron-capture elements detected in the near-infrared spectra, and estimate total elemental abundances of Se, Br, Kr, Rb, and Te after correcting for unobserved ions. Comparison of our derived enrichments to theoretical predictions from AGB evolutionary models shows reasonable agreement for solar metallicity progenitor stars of

Carbon abundances and radial gradients in NGC300 and other nearby spiral galaxies

sim