Chemical abundances in Galactic planetary nebulae with<i>Spitzer</i>spectra

García-Hernández, D. A.; Górny, S. K.

doi:10.1051/0004-6361/201423620

Cited by 34 publications

(46 citation statements)

References 69 publications

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“…A tight correlation is found between Ne and O abundances similar to that found in all other sample of PNe and H ii regions (Henry 1989;García-Hernández & Górny 2014;García-Rojas et al 2016). The linear fit for PNe is 12 + log(Ne/H) = (1.74 ± 0.49) × (12 + log(O/H)) − (6.60 ± 4.05), with R 2 = 0.70.…”

Section: Ne/o Abundance Ratiossupporting

confidence: 78%

Kinematic and chemical study of planetary nebulae and H II regions in NGC 3109

Flores-Durán

Peña

Ruíz

2017

A&A

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Aims. We present high-resolution spectroscopy of a number of planetary nebulae (PNe) and H ii regions distributed along the dwarf irregular galaxy NGC 3109 and compare their kinematical behavior with that of H i data. We aim to determine if there is a kinematical connection among these objects. We also aim to determine the chemical composition of some PNe and H ii regions in this galaxy and discuss it in comparison with stellar evolution models.Methods. Data for eight PNe and one H ii region were obtained with the high-resolution spectrograph Magellan Inamori Kyocera Echelle (MIKE) at Las Campanas Observatory, Chile. Data for three PNe, six compact H ii regions, and nine knots or clumps in extended H ii regions were obtained with the high-resolution spectrograph Manchester Echelle Spectrometer (MES) attached to the 2.1m telescope at the Observatorio Astronómico Nacional, SPM, B.C., Mexico. An additional object was obtained from The SPM Catalogue of Extragalactic Planetary Nebulae. Thus, in total we have high-quality data for nine of the 20 PNe detected in this galaxy, and many H ii regions. In the wavelength calibrated spectra, the heliocentric radial velocities were measured with a precision better than 7.8 km s −1 . Data for blue supergiant stars were collected from the literature to be included in the analysis. The heliocentric radial velocities of the different objects were compared to the velocities of the H i disk at the same position. Physical conditions and ionic abundances of PNe and H ii regions were obtained from the emission lines, and we used recent ionization correction factors to derive the total chemical abundances.Results. From the analysis of radial velocities we found that H ii regions in NGC 3109 share the kinematics of the H i disk at the same projected position with very low dispersion in velocities. Blue supergiant stars and PNe rotate in the same direction as the H i disk but these objects have much larger dispersion; this larger dispersion is possibly because these objects belong to a different population that is located in the central stellar bar reported for this galaxy. From the chemical abundance determinations we demonstrate that PNe are enriched in O and Ne. The average O abundance in H ii regions is 12 + log O/H = 7.74 ± 0.09 and PNe show significantly higher oxygen abundance by 0.43 dex in average. Ne abundance are about three times larger in PNe than in H ii regions. This is a very important result showing that because of the low metallicity in the galaxy, O and Ne in PNe have been enriched by their progenitors in nucleosynthesis processes and brought to the surface during third dredge-up events. Our PN abundances are better reproduced by some nonstandard stellar evolution models for a metallicity of Z = 0.001, similar to the metallicity of H ii regions. Abundances in H ii regions show no metallicity gradient in this galaxy. We discuss a possible connection between the kinematics and chemistry.

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Section: Ne/o Abundance Ratiossupporting

confidence: 78%

Kinematic and chemical study of planetary nebulae and H II regions in NGC 3109

Flores-Durán

Peña

Ruíz

2017

A&A

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“…5.4. (Henry 1989;García-Hernández & Górny 2014). This has been interpreted as Ne not being strongly altered by AGB evolution so that O and Ne grow in lock-step during the chemical evolution of galaxies.…”

Section: He N and Omentioning

confidence: 99%

“…From the analysis of a sample of Galactic disk and bulge double chemistry (DC), O-rich dust (OC), and C-rich dust (CC) PNe, García-Hernández & Górny (2014) found that the average Ne/O at Z = 0.02 for their DC and OC PNe was slightly larger than those predicted by the models by Karakas (2010) without a partial mixed zone (PMZ); therefore, they conclude that including and varying the size of a PMZ can solve the observed behaviour. However, that is exactly the opposite of what we found in our sample.…”

Section: Testing Other Stellar Evolution Modelsmentioning

confidence: 99%

The planetary nebulae and H II regions in NGC 6822 revisited. Clues to AGB nucleosynthesis

García‐Rojas

Peña

Flores-Durán

et al. 2016

A&A

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Aims. The chemical behaviour of an ample sample of planetary nebulae (PNe) in NGC 6822 is analysed.Methods. Spectrophotometric data of 11 PNe and two H  regions were obtained with the OSIRIS spectrograph attached to the Gran Telescopio Canarias. Data for other 13 PNe and three H  regions were retrieved from the literature. Physical conditions and chemical abundances of O, N, Ne, Ar, and S were derived in a consistent way for 19 PNe and 4 H  regions.Results. Abundances in the PNe sample are widely distributed showing 12 + log (O/H) from 7.4 to 8.2 and 12 + log (Ar/H) from 4.97 to 5.80. Two groups of PNe can be differentiated: one old with low metallicity (12 + log (O/H) < 8.0 and 12 + log (Ar/H) < 5.7) and another younger one with metallicities similar to the values for H  regions. The old objects are distributed in a larger volume than the young ones. An important fraction of PNe (over 30%) was found to be highly N-rich (Peimbert Type I PNe). Such PNe occur at any metallicity. In addition, about 60% of the sample presents high ionization (He ++ /He ≥ 0.1), possessing a central star with effective temperature higher than 100 000 K. Possible biases in the sample are discussed. From comparison with stellar evolution models by Karakas (2010) and Fishlock et al. (2014) of the observed N/O abundance ratios, our PNe should have had initial masses that are lower than 4 M , although if the comparison is made with Ne vs. O abundances, the initial masses should have been lower than 2 M . It appears that these models of stars of 2−3 M are producing too much 22 Ne in the stellar surface at the end of the AGB. On the other hand, the comparison with another set of stellar evolution models with a different treatment of convection and on the assumptions about the overshoot of the convective core during the core H-burning phase, provided there is reasonable agreement between the observed and predicted N/O and Ne/H ratios if initial masses of more massive stars are about 4 M .

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“…We have compared our abundance determinations for sample A objects with the recent study made by García-Hernández & Górny (2014) for a large sample of PNe compiled from the literature. All our sample A PNe, with the exception of M 1-33 were studied by García-Hernández & Górny (2014).…”

Section: Comparison With Other Abundance Determinations In the Literamentioning

confidence: 99%

“…Low-resolution (R∼1000) optical spectroscopy of a significant portion of this sample of compact Galactic disc and bulge PNe with Spitzer spectra allowed García-Hernández & Górny (2014) to derive the nebular abundances of He, N, O, Ar, Ne, S, and Cl. Remarkably, DC PNe both with crystalline and amorphous silicate dust features (DC cr and DC am+cr ) in the bulge and disc display median He and N (and N/O) abundances higher than those observed in PNe with only O-rich or C-rich dust (see Figs.…”

Section: Introductionmentioning

confidence: 99%

C/O ratios in planetary nebulae with dual-dust chemistry from faint optical recombination lines

García‐Rojas

Delgado-Inglada

García–Hernández

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We present deep high-resolution (R∼15,000) and high-quality UVES optical spectrophotometry of nine planetary nebulae with dual-dust chemistry. We compute physical conditions from several diagnostics. Ionic abundances for a large number of ions of N, O, Ne, S, Cl, Ar, K, Fe and Kr are derived from collisionally excited lines. Elemental abundances are computed using state-of-the-art ionization correction factors. We derive accurate C/O ratios from optical recombination lines. We have re-analyzed additional high-quality spectra of 14 PNe from the literature following the same methodology. Comparison with asymptotic giant branch models reveal that about half of the total sample objects are consistent with being descendants of low-mass progenitor stars (M < 1.5 M ). Given the observed N/O, C/O, and He/H ratios, we cannot discard that some of the objects come from more massive progenitor stars (M > 3-4 M ) that have suffered a mild HBB. None of the objects seem to be descendant of very massive progenitors. We propose that in most of the planetary nebulae studied here, the PAHs have been formed through the dissociation of the CO molecule. The hypothesis of a last thermal pulse that turns O-rich PNe into C-rich PNe is discarded, except in three objects, that show C/O>1. We also discuss the possibility of a He pre-enrichment to explain the most Heenriched objects. We cannot discard another scenarios like extra mixing, stellar rotation or binary interactions to explain the chemical abundances behaviour observed in our sample.

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Chemical abundances in Galactic planetary nebulae withSpitzerspectra

Cited by 34 publications

References 69 publications

Kinematic and chemical study of planetary nebulae and H II regions in NGC 3109

Kinematic and chemical study of planetary nebulae and H II regions in NGC 3109

The planetary nebulae and H II regions in NGC 6822 revisited. Clues to AGB nucleosynthesis

C/O ratios in planetary nebulae with dual-dust chemistry from faint optical recombination lines

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