Related papers: Planetary Nebulae as a Chemical Evolution Tool: Ab…
In this review I outline some ideas in chemical evolution, necessary for understanding the evolution of galaxies from measured elemental abundance ratios. I then discuss abundance results from studies of Local Group dwarf galaxies and the…
We have developed a grid of chemical evolution models applied to dwarf isolated galaxies, using \cite{gav05} yields. The input data enclose different star formation efficiencies, galaxy mass and collapse time values. The result is a wide…
The amount of nebular gas that a planet can bind is limited by its cooling rate, which is set by the opacity of its envelope. Accreting dust and pebbles contribute to the envelope opacity and, thus, influence the outcome of planet…
We have obtained spectra of 16 planetary nebulae in the disk of M31 and determined the abundances of He, N, O, Ne, S and Ar. Here we present the median abundances and compare them with previous M31 PN disk measurements and with PNe in the…
Modern tools for modeling stellar evolution, such as MESA (Modules for Experiments in Stellar Astrophysics), offer state-of-the-art implementations of stellar theories. However, this parametric approach introduces many free parameters that…
We have selected a group of 100 evolved planetary nebulae (PNe) and study their kinematics based upon spatially-resolved, long-slit, echelle spectroscopy. The data have been drawn from the San Pedro M\'artir Kinematic Catalogue of PNe…
Chemical evolution models are useful for understanding the formation and evolution of stars and galaxies. Model predictions will be more robust as more observational constraints are used. We present chemical evolution models for the dwarf…
The recent introduction of high resolution/large spectral range spectrographs provided the opportunity to investigate in detail the chemical composition of classical Cepheids. This paper is focussed on new abundance determinations for iron…
While there has been significant progress in our understanding of the origin and evolu-tion of planetary nebulae in the last 50 years, there remain several unsolved problems. These include the true 3D morphological structure of the nebulae,…
The failure of S and O abundances in most planetary nebulae to display the same strong direct correlation that is observed in extragalactic H II regions represents one of the most perplexing problems in the area of PN abundances today.…
We consider the oxygen abundance distributions for a sample of massive spiral galaxies from the MaNGA survey in which the radial abundance gradient flattens to a constant value outside of the outer break radius, Rb,outer. The outer break…
We present a systematic study of line widths in the [\ion{O}{3}]$\lambda$5007 and H$\alpha$ lines for a sample of 86 planetary nebulae in the Milky Way bulge based upon spectroscopy obtained at the \facility{Observatorio Astron\'omico…
The evolution of radial gradients of metallicity in disk galaxies and its relation with the disk formation are not well understood. Theoretical models of galactic chemical evolution make contrasting predictions about the time evolution of…
Planetary nebulae (PN) represent the evolutionary fate of the asymptotic giant branch (AGB) stellar envelopes, thus are ideally suited to study the chemical impact of AGB stars. Stellar evolution predict elemental enrichment through the AGB…
We derive stellar population parameters and radial gradients within 0.65 $R_e$ for spatially resolved spectra of 2968 early-type galaxies from MaNGA, spanning stellar velocity dispersions ($\sigma$) of 50--340 km s$^{-1}$. Light-weighted…
Most of the chemical evolution models are not very reliable for the last 5~Gyr of galactic evolution; this is mainly because abundance gradients found in the literature show a big dispersion for young objects; a big culprit of this is the…
Recent work (Corradi et al. 2015, Jones et al. 2016) has shown that the phenomenon of extreme abundance discrepancies, where recombination line abundances exceed collisionally excited line abundances by factors of 10 or more, seem to be…
Using spectroscopic data presented in Magrini et al. (2003), we have analyzed with the photoionization code CLOUDY 94.00 (Ferland et al. 1998) 11 Planetary Nebulae belonging to the spiral galaxy M 33. Central star temperatures and nebular…
The stars of the middle main sequence have relatively quiescent outer layers, and unusual chemical abundance patterns may develop in their atmospheres. The presence of chemical peculiarities reveal the action of such subsurface phenomena as…
We present emission line strengths, abundances, and element ratios (X/O for Ne, S, Cl, and Ar) for a sample of 38 Galactic disk planetary nebulae (PNe) consisting primarily of Peimbert classification Type I. Spectrophotometry for these PNe…