The Iron Abundance in Galactic Planetary Nebulae

Delgado-Inglada, G.; Rodríguez, Mónica; Mampaso, A.; Viironen, K.

doi:10.1088/0004-637x/694/2/1335

Cited by 49 publications

(69 citation statements)

References 96 publications

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“…We can see from Figure 1 Even taking into account all the considerations mentioned above that could change the iron depletions factors shown in the right axes of Figure 1, we can conclude that a significant fraction of our sample PNe have more than ∼90% of their iron atoms deposited into dust grains. In agreement with our previous findings in a smaller sample of PNe (Delgado-Inglada et al 2009), the range of depletions is high, with differences reaching a factor of ∼100. These differences can be related to the PNe ages or grain compositions, maybe reflecting different efficiencies of the grain formation and destruction processes, an issue that we will explore further in the following sections.…”

Section: Iron Depletionssupporting

confidence: 92%

“…Second, whereas Delgado-Inglada et al (2009) derive the final n e as the weighted mean of the values implied by the available diagnostic ratios, here the final n e is the median value of the density distribution obtained from averaging the n e values calculated in each run of the Monte Carlo simulation. One of the objects with significant differences is NGC 3587, where Delgado-Inglada et al (2009) used the [S ii] density diagnostic and found n e < 100 cm −3 , whereas here we also use the [O ii] diagnostic and find n e = 2400 cm −3 . This change in n e implies a change in T e [N ii] from 9800 K to 10900 K. In general, T e differences are smaller, around 100 K in most of the objects.…”

Section: Physical Conditionsmentioning

confidence: 99%

“…As in Delgado-Inglada et al (2009), we explored possible correlations between the iron depletions and different nebular and stellar parameters such as the electron density, the nebular radius, the surface brightness, the effective temperature of the central star, or the nebular morphology. In agreement with Delgado-Inglada et al (2009), we do not find any obvious correlation.…”

Section: O-rich Features: Amorphous and Crystalline Silicatesmentioning

confidence: 99%

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C/O Abundance Ratios, Iron Depletions, and Infrared Dust Features in Galactic Planetary Nebulae

Delgado-Inglada

Rodríguez

2014

ApJ

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We study the dust present in 56 Galactic planetary nebulae (PNe) through their iron depletion factors, their C/O abundance ratios (in 51 objects), and the dust features that appear in their infrared spectra (for 33 objects). Our sample objects have deep optical spectra of good quality, and most of them also have ultraviolet observations. We use these observations to derive the iron abundances and the C/O abundance ratios in a homogeneous way for all the objects. We compile detections of infrared dust features from the literature and we analyze the available Spitzer/IRS spectra. Most of the PNe have C/O ratios below one and show crystalline silicates in their infrared spectra. The PNe with silicates have C/O < 1, with the exception of Cn 1-5. Most of the PNe with dust features related to C-rich environments (SiC or the 30 μm feature usually associated to MgS) have C/O 0.8. Polycyclic aromatic hydrocarbons are detected over the full range of C/O values, including 6 objects that also show silicates. Iron abundances are low in all the objects, implying that more than 90% of their iron atoms are deposited into dust grains. The range of iron depletions in the sample covers about two orders of magnitude, and we find that the highest depletion factors are found in C-rich objects with SiC or the 30 μm feature in their infrared spectra, whereas some of the O-rich objects with silicates show the lowest depletion factors.

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Section: Iron Depletionssupporting

confidence: 92%

Section: Physical Conditionsmentioning

confidence: 99%

Section: O-rich Features: Amorphous and Crystalline Silicatesmentioning

confidence: 99%

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C/O Abundance Ratios, Iron Depletions, and Infrared Dust Features in Galactic Planetary Nebulae

Delgado-Inglada

Rodríguez

2014

ApJ

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“…Those authors also derived another ICF using photoionionisation models but it seems to introduce an unexpected trend with the degree of ionisation (Delgado Inglada et al 2009). As it can be noted in Table 7, we have not calculated total abundances for aperture no.…”

Section: Total Abundancesmentioning

confidence: 99%

The chemical composition of Galactic ring nebulae around massive stars

Esteban

Mesa‐Delgado

Morisset

et al. 2016

Mon. Not. R. Astron. Soc.

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We present deep spectra of ring nebulae associated with Wolf-Rayet (WR) and O-type stars: NGC 6888, G2.4+1.4, RCW 58, S 308, NGC 7635 and RCW 52. The data have been taken with the 10m Gran Telescopio Canarias and the 6.5m Clay Telescope. We extract spectra of several apertures in some of the objects. We derive C 2+ and O 2+ abundances from faint recombination lines in NGC 6888 and NGC 7635, permitting to derive their C/H and C/O ratios and estimate the abundance discrepancy factor (ADF) of O 2+ . The ADFs are larger than the typical ones of normal H ii regions but similar to those found in the ionised gas of star-forming dwarf galaxies. We find that chemical abundances are rather homogeneous in the nebulae where we have spectra of several apertures: NGC 6888, NGC 7635 and G2.4+1.4. We obtain very high values of electron temperature in a peripheral zone of NGC 6888, finding that shock excitation can reproduce its spectral properties. We find that all the objects associated with WR stars show N enrichment. Some of them also show He enrichment and O deficiency as well as a lower Ne/O than expected, this may indicate the strong action of the ON and NeNa cycles. We have compared the chemical composition of NGC 6888, G2.4+1.4, RCW 58 and S 308 with the nucleosynthesis predicted by stellar evolution models of massive stars. We find that non-rotational models of stars of initial masses between 25 and 40 M ⊙ seem to reproduce the observed abundance ratios of most of the nebulae.

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“…In this table we also present the Fe/H value by Venn et al (2001) from A-type supergiants. Because most of the Fe in H ii regions and PNe is trapped in dust grains (Peimbert & Peimbert 2010;Shields 1978;Delgado-Inglada et al 2009), we do not present the gaseous Fe/H abundance. In this table we do not show either He, C or N abundances for PNe because PN progenitors strongly modify these element abundances during their evolution.…”

Section: Observational Constraintsmentioning

confidence: 99%

Planetary nebulae as observational constraints in chemical evolution models for NGC 6822

Hernández-Martínez

Carigi

Peña

et al. 2011

A&A

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Aims. Chemical evolution models are useful for understanding the formation and evolution of stars and galaxies. Model predictions will be more robust when more observational constraints are used. We present chemical evolution models for the dwarf irregular galaxy NGC 6822 using chemical abundances of old and young planetary nebulae (PNe) and H ii regions as observational constraints. We use two sets of chemical abundances, one derived from collisionally excited lines (CELs) and one from recombination lines (RLs). We use our models as a tool to distinguish between both procedures for abundance determinations. Methods. In our chemical evolution code the chemical contribution of low and intermediate mass stars is time-delayed, while for the massive stars the chemical contribution follows the instantaneous recycling approximation. Our models have two main free parameters: the mass-loss rate of a well-mixed outflow and the upper mass limit, M up , of the initial mass function (IMF). To reproduce the gaseous mass and the present-day O/H value we need to vary the outflow rate and the M up value. Results. We calculate two models with different M up values that reproduce the constraints adequately. The abundances of old PNe agree with our models and support the star-formation history derived independently from photometric data. Both require an early wellmixed wind, lasting 5.3 Gyr, to reproduce the observed gaseous mass in the galaxy. In addition, by assuming a fraction of binaries producing SNIa of 1%, the models fit the Fe/H abundance ratio as derived from A supergiants. The first model (M4C), which assumes M up = 40 M , fits within errors smaller than 2σ the O/H, Ne/H, S/H, Ar/H and Cl/H abundances obtained from CELs for old and young PNe and H ii regions. The second model (M1R), which adopts M up = 80 M , reproduces within 2σ errors the O/H, C/H, Ne/H and S/H abundances adopted from RLs. Both models reproduce the increase of the O, Ne, S, and Ar elements during the last 6 Gyr. We are not able to match the observed N/O ratios in either case, which suggests that the N yields of LIMS need to be improved. Model M1R does not provide a good fit to the Cl/H and Ar/H ratios, because the SN yields of those elements for m > 40 M are not adequate and need to be improved (two sets of yields were tried). From these results we are unable to conclude which set of abundances (the one from CELs or the one from RLS) represents the real abundances in the ISM better. We discuss the predicted ΔY/ΔO values, finding that the value from model M1R agrees better with data for other galaxies from the literature than the value from model M4C.

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The Iron Abundance in Galactic Planetary Nebulae

Cited by 49 publications

References 96 publications

C/O Abundance Ratios, Iron Depletions, and Infrared Dust Features in Galactic Planetary Nebulae

C/O Abundance Ratios, Iron Depletions, and Infrared Dust Features in Galactic Planetary Nebulae

The chemical composition of Galactic ring nebulae around massive stars

Planetary nebulae as observational constraints in chemical evolution models for NGC 6822

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