相关论文: The Iron abundance in Galactic Planetary Nebulae

We have made the first attempt to derive the chemical properties of the Galactic disc at its very central part using high-resolution infrared spectroscopic observations of four classical Cepheids. Those stars are located at Galactocentric…

Our understanding of the chemical evolution of the Galactic bulge requires the determination of abundances in large samples of giant stars and planetary nebulae (PNe). We discuss PNe abundances in the Galactic bulge and compare these…

Globular clusters are tracers of the history of star formation and chemical enrichment in the early Galaxy. Their abundance pattern can help understanding their chemical enrichment processes. In particular, the iron-peak elements have been…

We have derived azimuthally-averaged radial iron abundance profiles of the X-ray gas contained within 12 clusters of galaxies with redshift 0.03 < z < 0.2 observed with BeppoSAX. We find evidence for a negative metal abundance gradient in…

In this study, we investigate the physical and chemical properties of planetary nebulae (PNe) from the Milky Way Galaxy using the largest number of sources to date, with 1,449 True PNe from the HASH database. Among the Galactic components…

We calculate filling factors (${\varepsilon}$) and ionized masses (M$_{\rm i}$) for a total of 84 galactic and extragalactic planetary nebulae (PNe) at known distances. To do these calculations, we have chosen forbidden line electron…

Low- and intermediate-mass ($\rm 0.8~M_\odot < M < 8~M_\odot$) stars that evolve into planetary nebulae (PNe) play an important role in tracing and driving Galactic chemical evolution. Spectroscopy of PNe enables access to both the initial…

M 2 has been claimed to posses three distinct stellar components that are enhanced in iron relative to each other. We use equivalent width measurements from 14 red giant branch stars from which Yong et al. detect a $\sim$0.8 dex wide,…

Atomic species in the interstellar medium (ISM) transition out of their gas phase mainly by depletion onto dust. In this study, we examine if there is any change to the spectral line ratio predictions from a photoionization model of the…

We use a large grid of photoionization models that are representative of observed planetary nebulae (PNe) to derive ionization correction factors (ICFs) for sodium, potassium, and calcium. In addition to the analytical expressions of the…

We present new low-resolution (R~800) optical spectra of 22 Galactic PNe with Spitzer spectra. These data are combined with recent optical spectroscopic data available in the literature to construct representative samples of compact (and…

We report abundance analysis for 30 M giant stars in two inner Galactic bulge fields at (l,b)=(0,-1.75) deg and at (l,b)=(1,-2.65) deg, based on R=25,000 infrared spectroscopy from 1.5-1.8um using NIRSPEC at the Keck II telescope. We find…

We investigated the infrared (IR) dust emission from PN IC 418, using a detailed model controlled by a previous determination of the stellar properties and the characteristics of the photoionized nebula, keeping as free parameters the dust…

We report the first abundance analysis of 17 M giant stars in the inner Galactic bulge at $(l,b)=(0\deg,-1\deg)$, based on $R=25,000$ infrared spectroscopy $(1.5-1.8 ~\mu \rm m)$ using NIRSPEC at the Keck telescope. Based on their…

We have obtained spectrophotometric observations of 41 anticenter planetary nebulae (PNe) located in the disk of the Milky Way. Electron temperatures and densities, as well as chemical abundances for He, N, O, Ne, S, Cl, and Ar were…

For the first time, neon abundance has been derived in the narrow line region from a sample of Seyfert~2 nuclei. In view of this, we compiled from the literature fluxes of optical and infrared (IR) narrow emission lines for 35 Seyfert 2…

(Abridged) Planetary nebulae (PNe) around Wolf-Rayet [WR] central stars ([WR]PNe) constitute a particular photoionized nebula class that represents about 10% of the PNe with classified central stars. We analyse deep high-resolution…

We discuss oxygen and iron abundance patterns in K and M red-giant members of the Galactic bulge and in the young and massive M-type stars inhabiting the very center of the Milky Way. The abundance results from the different bulge studies…

We present MUSE deep integral-field unit spectroscopy of three planetary nebulae(PNe) with high abundance discrepancy factors (ADF > 20): NGC 6778, M 1-42 and Hf 2-2. We have constructed flux maps for more than 40 emission lines, and use…

Estimates of the gas temperature in planetary nebulae obtained from the [O III] emission line ratio and from the Balmer discontinuity indicate differences reaching up to 6000 K (Liu and Danziger 1993). The [O III] temperature is commonly…