Sulfur, Chlorine, and Argon Abundances in Planetary Nebulae. IV. Synthesis and the Sulfur Anomaly

Henry, R. B. C.; Kwitter, K. B.; Balick, Bruce

doi:10.1086/382242

Cited by 145 publications

(239 citation statements)

References 61 publications

(87 reference statements)

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“…We obtain that the mean value of the Cl/O ratio across the Galactic disc is log(Cl/O) = −3.42 ± 0.06, consistent with previous determinations based on PNe data (e.g. Henry et al 2004) and from the recommended solar photospheric and meteoritic abundances compiled by Lodders et al (2009).…”

Section: Discussionsupporting

confidence: 90%

“…From our data, we have determined the weighted mean of the Cl/O ratio across the Galactic disc and this is log(Cl/O) = −3.42 ± 0.06. Henry et al (2004) compile a number of determinations of the Cl/O ratio based on PNe and H ii region observations, and the logarithmic values range from −3.67 to −3.30. Therefore, our mean ratio is consistent with those previous calculations.…”

Section: The Galactic Cl/h Gradientmentioning

confidence: 99%

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The radial abundance gradient of chlorine in the Milky Way

Esteban¹,

García‐Rojas²,

Pérez-Mesa³

2015

Mon. Not. R. Astron. Soc.

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We determine the radial abundance gradient of Cl in the Milky Way from H ii regions spectra. For the first time, the Cl/H ratios are computed by simply adding ionic abundances and not using an ionization correction factor (ICF ). We use a collection of published very deep spectra of Galactic H ii regions. We have re-calculated the physical conditions, ionic and total abundances of Cl and O using the same methodology and updated atomic data for all the objects. We find that the slopes of the radial gradients of Cl and O are identical within the uncertainties: −0.043 dex kpc −1 . This is consistent with a lockstep evolution of both elements. We obtain that the mean value of the Cl/O ratio across the Galactic disc is log(Cl/O) = −3.42 ± 0.06. We compare our Cl/H ratios with those determined from Cl 2+ abundances and using some available ICF schemes of the literature. We find that our total Cl abundances are always lower than the values determined using ICF s, indicating that those correction schemes systematically overestimate the contribution of Cl + and Cl 3+ species to the total Cl abundance. Finally, we propose an empirical ICF (Cl 2+ ) to estimate the Cl/H ratio in H ii regions.

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Section: Discussionsupporting

confidence: 90%

Section: The Galactic Cl/h Gradientmentioning

confidence: 99%

The radial abundance gradient of chlorine in the Milky Way

Esteban¹,

García‐Rojas²,

Pérez-Mesa³

2015

Mon. Not. R. Astron. Soc.

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“…Both H II regions and planetary nebulae serve as interstellar probes of alpha element abundances. We have measured abundances for the alpha elements O, Ne, S, Cl, and Ar in over 130 Galactic Types I and II and halo PNe in a consistent manner from our own optical (3600-9600Å) spectra (Henry, Kwitter, & Balick 2004). Figure 1 is a plot of Ne vs. O for a combined dataset containing H II regions, blue compact galaxies, and our sample of planetary nebulae.…”

Section: What Is the Sulfur Anomaly?mentioning

confidence: 75%

The Sulfur Abundance Anomaly in Planetary Nebulae

Henry

Skinner

Kwitter

et al. 2006

IAU

Self Cite

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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. Galactic chemical evolution models as well as large amounts of observational evidence from H II region studies support the contention that cosmic abundances of alpha elements such as O, Ne, S, Cl, and Ar increase together in lockstep. Yet abundance results from the Henry, Kwitter, & Balick (2004) database show a strong tendency for most PNe to have S abundances that are significantly less than expected from the observed level of O. One reasonable hypothesis for the sulfur anomaly is the past failure to properly measure the abundances of unseen ionization stages above S^+2. Future observations with Spitzer will allow us to test this hypothesis.Comment: Two pages, two figures. Contributed paper, IAU Symp. 234, ``Planetary Nebulae in our Galaxy and Beyond.'

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“…Planetary nebula gradients in the Milky Way indicate that the metallicity decreases inside out by 0.01 to 0.07 dex kpc −1 (e.g., Maciel & Quireza 1999;Henry et al 2004;Stanghellini et al 2006;Perinotto & Morbidelli 2006). The most recent of these studies seem to agree that the PN metallicity gradients are rather flat, i.e., their slope is not steeper than ∼−0.02 dex kpc −1 , and only slightly shallower than that derived from H ii regions, implying that the Galactic metallicity gradient does not vary very much within the time frame of Galactic evolution.…”

Section: Introductionmentioning

confidence: 99%

The population of planetary nebulae and H II regions in M 81

Stanghellini¹,

Magrini

Villaver³

et al. 2010

A&A

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Context. M 81 is an ideal laboratory to investigate the galactic chemical and dynamical evolution through the study of its young and old stellar populations.Aims. We analyze the chemical abundances of planetary nebulae and H ii regions in the M 81 disk for insight on galactic evolution, and compare it with that of other galaxies, including the Milky Way.Methods. We acquired Hectospec/MMT spectra of 39 PNe and 20 H ii regions, with 33 spectra viable for temperature and abundance analysis. Our PN observations represent the first PN spectra in M 81 ever published, while several H ii region spectra have been published before, although without a direct electron temperature determination. We determine elemental abundances of helium, nitrogen, oxygen, neon, sulfur, and argon in PNe and H ii regions, and determine their averages and radial gradients. Results. The average O/H ratio of PNe compared to that of the H ii regions indicates a general oxygen enrichment in M 81 in the last ∼10 Gyr. The PN metallicity gradient in the disk of M 81 is Δlog(O/H)/ΔR G = −0.055 ± 0.02 dex/kpc. Neon and sulfur in PNe have a radial distribution similar to that of oxygen, with similar gradient slopes. If we combine our H ii sample with the one in the literature we find a possible mild evolution of the gradient slope, with results consistent with gradient steepening with time. Additional spectroscopy is needed to confirm this trend. There are no type I PNe in our M 81 sample, consistently with the observation of only the brightest bins of the PNLF, the galaxy metallicity, and the evolution of post-AGB shells. Conclusions. Both the young and the old populations of M 81 disclose shallow but detectable negative radial metallicity gradient, which could be slightly steeper for the young population, thus not excluding a mild gradients steepening with the time since galaxy formation. During its evolution M 81 has been producing oxygen; its total oxygen enrichment exceeds that of other nearby galaxies.

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Sulfur, Chlorine, and Argon Abundances in Planetary Nebulae. IV. Synthesis and the Sulfur Anomaly

Cited by 145 publications

References 61 publications

The radial abundance gradient of chlorine in the Milky Way

The radial abundance gradient of chlorine in the Milky Way

The Sulfur Abundance Anomaly in Planetary Nebulae

The population of planetary nebulae and H II regions in M 81

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