Chemical abundances of planetary nebulae towards the Galactic anticenter

Costa, R. D. D.; Uchida, M. M. M.; Maciel, W. J.

doi:10.1051/0004-6361:20034539

Cited by 63 publications

(51 citation statements)

References 36 publications

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“…These metallic abundances agree with the expected [Fe/H] at such a distance, i.e., [Fe/H] ≈ −0.4 dex to [Fe/H] ≈ −0.6 dex and this puts these two clusters on the plateau already devised through analysis of other objects such as isolated hot stars (Cayrel de Strobel et al 1997;Daflon & Cunha 2004), planetary nebula (Costa et al 2004), Cepheids (Fry & Carney 1997), etc., though more limited in distance. We cannot argue against or in favour of the existence of a radial metallicity gradient (see Chen et al 2003;Koen & Lombard 2007).…”

Section: The Clusters and Spiral Structuresupporting

confidence: 84%

Open clusters in the Third Galactic Quadrant III. Alleged binary clusters

Vazquez

Moitinho

Carraro³

et al. 2010

A&A

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Aims. We aim to determine accurate distances and ages of eight open clusters in order to: (1) assess their possible binarity (2) provide probes to trace the structure of the Third Galactic Quadrant. Methods. Cluster reddenings, distances, ages and metallicities are derived from ZAMS and isochrone fits in UBVRI photometric diagrams. Field contamination is reduced by restricting analysis to stars within the cluster limits derived from star counts. Further membership control is done by requiring that stars have consistent positions in several diagrams and by using published spectral types. Results. The derived distances, ages and metallicities have shown that none of the analysed clusters compose binary/double systems. Of the four candidate pairs, only NGC 2383/NGC 2384 are close to each other, but have different metallicities and ages. Ruprecht 72 and Ruprecht 158 are not clusters but fluctuations of the field stellar density. Haffner 18 is found to be the superposition of two stellar groups at different distances: Haffner 18(1) at 4.5 kpc and Haffner 18(2) between 9.5 and 11.4 kpc from the Sun. The derived distances and ages have been used to situate the clusters in the Galactic context. In particular, young stellar groups trace spiral structure at large Galactocentric radii. At least two clusters formed during the last few 10 8 yr in an interstellar medium with less than solar abundances. Conclusions. In contrast with the LMC, double clusters are apparently rare, or even non existent, in the undisturbed environment of the Third Galactic Quadrant. This leaves open the question of whether binary clusters form more easily toward denser and more violent regions of the Milky Way such as the inner Galaxy.

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Section: The Clusters and Spiral Structuresupporting

confidence: 84%

Open clusters in the Third Galactic Quadrant III. Alleged binary clusters

Vazquez

Moitinho

Carraro³

et al. 2010

A&A

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“…Frinchaboy et al (2013) measured a single radial fit of −0.09 dex kpc −1 for their sample of open clusters observed with APOGEE, but find that it is potentially better fit with two components: a steeper gradient of −0.2 dex kpc −1 between 7.9 < R < 10 kpc, and a flat radial gradient for clusters with R > 10 kpc. Several previous studies (Costa et al 2004;Jacobson et al 2011b;Yong et al 2012) have shown evidence for a transition to a flat radial gradient at large Galactocentric radii in the plane, with the transition occurring between 10 and 14 kpc. This flattening of the radial gradient is not observed with Cepheids Luck & Lambert 2011;Lemasle et al 2013).…”

Section: Intermediate Radiimentioning

confidence: 85%

Chemical Cartography With Apogee: Large-Scale Mean Metallicity Maps of the Milky Way Disk

Hayden¹,

Holtzman²,

Bovy³

et al. 2014

173

195

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We present Galactic mean metallicity maps derived from the first year of the SDSS-III APOGEE experiment. Mean abundances in different zones of projected Galactocentric radius (0 < R < 15 kpc) at a range of heights above the plane (0 < |z| < 3 kpc), are derived from a sample of nearly 20,000 giant stars with unprecedented coverage, including stars in the Galactic mid-plane at large distances. We also split the sample into subsamples of stars with low-and high-[α/M] abundance ratios. We assess possible biases in deriving the mean abundances, and find that they are likely to be small except in the inner regions of the Galaxy. A negative radial metallicity gradient exists over much of the Galaxy; however, the gradient appears to flatten for R < 6 kpc, in particular near the Galactic mid-plane and for low-[α/M] stars. At R > 6 kpc, the gradient flattens as one moves off the plane, and is flatter at all heights for high-[α/M] stars than for low-[α/M] stars. Alternatively, these gradients can be described as vertical gradients that flatten at larger Galactocentric radius; these vertical gradients are similar for both low-and high-[α/M] populations. Stars with higher [α/M] appear to have a flatter radial gradient than stars with lower [α/M]. This could suggest that the metallicity gradient has grown steeper with time or, alternatively, that gradients are washed out over time by migration of stars.

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“…Some authors have suggested a bimodal distribution of the oxygen abundances (Costa et al 2004;Magrini et al 2009;Yong et al 2012;Korotin et al 2014 and references therein) with a flattening starting at around 9-13 kpc from the Galactic centre. Korotin et al (2014), for example, suggest a double linear distribution with a slope of −0.056 dex kpc −1 until about R gc = 12 kpc and a flatter one of −0.033 dex kpc −1 at more dis- …”

Section: Oxygenmentioning

confidence: 99%

CNO abundances and carbon isotope ratios in evolved stars of the open clusters NGC 2324, NGC 2477, and NGC 3960

Tautvaišienė

Drazdauskas

Bragaglia

et al. 2016

A&A

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Aims. Our main aim is to determine carbon-to-nitrogen and carbon isotope ratios for evolved giants in the open clusters NGC 2324, NGC 2477, and NGC 3960, which have turn-off masses of about 2 M , and to compare them with predictions of theoretical models. Methods. High-resolution spectra were analysed using a differential synthetic spectrum method. Abundances of carbon were derived using the C 2 Swan (0,1) band heads at 5135 and 5635.

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Chemical abundances of planetary nebulae towards the Galactic anticenter

Cited by 63 publications

References 36 publications

Open clusters in the Third Galactic Quadrant III. Alleged binary clusters

Open clusters in the Third Galactic Quadrant III. Alleged binary clusters

Chemical Cartography With Apogee: Large-Scale Mean Metallicity Maps of the Milky Way Disk

CNO abundances and carbon isotope ratios in evolved stars of the open clusters NGC 2324, NGC 2477, and NGC 3960

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