- ID:
- ivo://CDS.VizieR/J/A+AS/94/399
- Title:
- Absolute fluxes and distances of PN
- Short Name:
- J/A+AS/94/399
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a complete list of averaged recalibrated absolute H{beta} fluxes, global (where possible) relative He II {lambda} 4686 fluxes, 5-GHz radio flux densities, and H{alpha}/H{beta} interstellar extinction constants for 778 Galactic planetary nebulae. The catalog provides much of the fundamental data required to generate Zanstra temperatures. When data with the lowest errors are selected, the optical and radio/optical extinctions show a peculiar correlation, with the radio values slightly high at low extinction and notably low at high extinction. The data are used, along with the best estimates of angular diameters, to calculate Shklovsky distances according to the Daub scheme on the scale used earlier by Cahn and Kaler (1971ApJS...22..319C). Use of this distance scale shows approximate equality of the death rates of optically thick and optically thin planetary nebulae. The method gives the correct distances to the Magellanic Clouds.
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- ID:
- ivo://CDS.VizieR/J/A+A/282/436
- Title:
- Abundance gradients from disk PNs
- Short Name:
- J/A+A/282/436
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A new determination of the radial abundance gradients of O/H, Ne/H, S/H, and Ar/H is made for disk planetary nebulae, (PN), that is, those objects of Peimbert types I, II, and III. On the basis of a sample containing 200 nebulae, it can be concluded that these gradients are generally similar, and of the same order of magnitude as the O/H gradient displayed by galactic HII regions. Some distance-independent correlations confirm the accuracy of the abundances and support the interpretation of the gradients in terms of chemical evolution models. The time evolution of the abundance gradients in the Milky Way is investigated, and their variation with the types of PN are compared with predictions of chemical evolution models.
- ID:
- ivo://CDS.VizieR/J/A+A/521/A3
- Title:
- Abundances in HII regions and PNe of M81
- Short Name:
- J/A+A/521/A3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- M81 is an ideal laboratory to investigate the galactic chemical and dynamical evolution through the study of its young and old stellar populations. We analyze the chemical abundances of planetary nebulae and HII regions in the M81 disk for insight on galactic evolution, and compare it with that of other galaxies, including the Milky Way.
- ID:
- ivo://CDS.VizieR/J/A+A/500/1089
- Title:
- Abundances in planetary nebulae
- Short Name:
- J/A+A/500/1089
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new spectroscopic data (90 objects) and derived plasma diagnostics and abundances of a sample of planetary nebulae in the direction of the Galactic center. The spectra were obtained in 2001/2002 with the 4-m class telescope at the Cerro Tololo Interamerican Observatory and the European Southern Observatory.
- ID:
- ivo://CDS.VizieR/J/A+A/427/231
- Title:
- Abundances in planetary nebulae
- Short Name:
- J/A+A/427/231
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new spectroscopic data (43 objects) and derived plasma diagnostics and abundances (164 objects) of a sample of planetary nebulae in the direction of the Galactic center. The spectra were obtained in July 2000 with the 1.9-m telescope at the South African Astronomical Observatory. The spectral coverage was 3500-7000{AA} with an average resolution of 1000.
- ID:
- ivo://CDS.VizieR/J/A+A/494/591
- Title:
- Abundances in planetary nebulae
- Short Name:
- J/A+A/494/591
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new plasma diagnostics and abundances of a sample of planetary nebulae located in the Galactic bulge (168 objects), the Galactic inner disk (61 objects) and in the LMC (110 objects).
- ID:
- ivo://CDS.VizieR/J/ApJS/218/25
- Title:
- Abundances in PNe. III: Se and Kr
- Short Name:
- J/ApJS/218/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The detection of neutron(n)-capture elements in several planetary nebulae (PNe) has provided a new means of investigating s-process nucleosynthesis in low-mass stars. However, a lack of atomic data has inhibited accurate trans-iron element abundance determinations in astrophysical nebulae. Recently, photoionization (PI) and recombination data were determined for Se and Kr, the two most widely detected n-capture elements in nebular spectra. We have incorporated these new data into the photoionization code Cloudy (Ferland et al. 2013RMxAA..49..137F). To test the atomic data, numerical models were computed for 15 PNe that exhibit emission lines from multiple Kr ions. We found systematic discrepancies between the predicted and observed emission lines that are most likely caused by inaccurate PI and recombination data. These discrepancies were removed by adjusting the Kr^+^-Kr^3+^ PI cross sections within their cited uncertainties and the dielectronic recombination rate coefficients by slightly larger amounts. From grids of models spanning the physical conditions encountered in PNe, we derive new, broadly applicable ionization correction factor (ICF) formulae for calculating Se and Kr elemental abundances. The ICFs were applied to our previous survey of near-infrared [KrIII] and [SeIV] emission lines in 120 PNe. The revised Se and Kr abundances are 0.1-0.3dex lower than former estimates, with average values of [Se/(O,Ar)]=0.12+/-0.27 and [Kr/(O,Ar)]=0.82+/-0.29, but correlations previously found between their abundances and other nebular and stellar properties are unaffected. We also find a tendency for high-velocity PNe that can be associated with the Galactic thick disk to exhibit larger s-process enrichments than low-velocity PNe belonging to the thin-disk population.
- ID:
- ivo://CDS.VizieR/J/A+A/279/567
- Title:
- Abundances of non-type I PNe in LMC
- Short Name:
- J/A+A/279/567
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectroscopic observations, plasma diagnostics and chemical composition of 15 non-type I planetary nebulae (PNe) in the Large Magellanic Cloud (LMC) are reported. Abundances of He, O, N, S, and Ar are determined and compared with recently obtained data for nebulae both in the Magellanic Clouds and in the Galaxy.
- ID:
- ivo://CDS.VizieR/J/A+A/552/A12
- Title:
- Abundances of PNe in NGC 300
- Short Name:
- J/A+A/552/A12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained deep spectroscopy of 26 planetary nebulae (PNe) and 9 compact HII regions in the nearby spiral galaxy NGC 300, and analyzed them together with the giant HII regions observed by Bresolin et al. (2009ApJ...700..309B). We have determined the physical properties of all those objects and their content in He, N, O, Ne, S and Ar in a consistent way. We find that compact HII regions have abundances similar to those of giant HII regions, while PNe have systematically larger N/O ratios and similar Ne/O and Ar/O ratios. We demonstrate that this nitrogen enhancement in PNe cannot be due to second dredge-up in the progenitor stars, since their initial masses are around 2-2.5M_{sun}_. An extra mixing process is required, perhaps be driven by rotation. Concerning the radial abundance distribution, PNe behave differently from HII regions: In the central parts, they show an average O/H smaller by 0.15dex. Their abundance dispersion at any galactocentric radius is significantly larger than for HII regions and many of them have O/H values higher than HII regions at the same galactocentric distance, suggesting that oxygen production in the PN progenitors in NGC 300 is common. PN abundance gradients in O/H, Ne/H and Ar/He are significantly shallower than those of HII regions. We argue that this indicates a steepening of the metallicity gradient in NGC 300 during the last Gr, rather than the effect of radial stellar motions.
- ID:
- ivo://CDS.VizieR/J/A+A/380/300
- Title:
- Abundances of PN towards Galactic bulge
- Short Name:
- J/A+A/380/300
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work we report spectrophotometric observations of a planetary nebula sample towards the galactic bulge. A total of 45 PNe was observed and their physical parameters (electron density and temperature) were derived. Ionic abundances were calculated using a three-level atom model and abundances were derived through ionisation correction factors. Results show low abundance objects at high galactic latitudes, indicating a possible vertical gradient inside the bulge. A few objects with low N/O ratio were found, which could have originated from old, low mass progenitors.
