The Problem of Orphanhood in Contemporary Russia: The Psychological Aspect

Денисенкова, Н С

doi:10.21557/ssc.47924960

Cited by 39 publications

(43 citation statements)

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“…However, Denisenkov & Denisenkova (1989) and Langer et al (1993) did not explain the observed abundance variations, with the simultaneous action of the Ne-Na and Mg-Al chains in the same temperature layers where the ON part of the complete CNO cycle was at work, until the late 80s and early 90s. The discovery of Na-O and Mg-Al Based on observations collected at ESO telescopes under programme 083.D-0208.…”

Section: Introductionmentioning

confidence: 82%

The normal chemistry of multiple stellar populations in the dense globular cluster NGC 6093 (M 80)

Carretta

Bragaglia

Gratton

et al. 2015

A&A

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We present the abundance analysis of 82 red giant branch stars in the dense, metal-poor globular cluster NGC 6093 (M 80), the largest sample of stars analysed in this way for this cluster. From high-resolution UVES spectra of 14 stars and intermediate resolution GIRAFFE spectra for the other stars we derived abundances of O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Ba, La, Ce, Pr, Nd, Sm, Eu. On our UVES metallicity scale the mean metal abundance of M 80 is [Fe/H] = −1.791 ± 0.006 ± 0.076 (±statistical ±systematic error) with σ = 0.023 (14 stars). M 80 shows star-to-star variations in proton-capture elements, and the extension of the Na-O anti-correlation perfectly fit the relations with (i) total cluster mass; (ii) horizontal branch morphology; and (iii) cluster concentration previously found by our group. The chemistry of multiple stellar populations in M 80 does not look extreme. The cluster is also a representative of halo globular clusters concerning the pattern of α-capture and Fe-group elements. However we found that a significant contribution from the s-process is required to account for the distribution of neutron-capture elements. A minority of stars in M 80 seem to exhibit slightly enhanced abundances of s-process species, compatible with those observed in M 22 and NGC 1851, although further confirmation from larger samples is required.

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Section: Introductionmentioning

confidence: 82%

The normal chemistry of multiple stellar populations in the dense globular cluster NGC 6093 (M 80)

Carretta

Bragaglia

Gratton

et al. 2015

A&A

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“…Early high resolution spectroscopic work revealed that clusters typically contain stars with similar heavy element abundances, most notably [Fe/H], 7 but with >0.5-1.0 dex star-to-star abundance variations for elements lighter than about Si (e.g., Cohen 1978;Peterson 1980;Sneden et al 1991;Kraft et al 1992;Pilachowski et al 1996;Gratton et al 2001). Furthermore, it was discovered that the light element abundance variations are (anti-)correlated with one another, and that the correlation patterns, such as the ONa anti-correlation and Na-Al correlation, are evidence that the gas from which the present-day low mass globular cluster stars formed was subjected to high-temperature protoncapture nucleosynthesis (e.g., Denisenkov & Denisenkova 1990;Langer et al 1993;Prantzos et al 2007). Except for a few notable cases (Koch et al 2009;Caloi & D'Antona 2011;Villanova et al 2013), recent large sample spectroscopic surveys (e.g., Carretta et al 2009bCarretta et al , 2009c have built upon this early work and cemented the idea that the correlated light element abundance variations are a characteristic common to perhaps all Galactic globular clusters (see also reviews by Kraft 1994;Gratton et al 2004Gratton et al , 2012.…”

Section: Introductionmentioning

confidence: 99%

A Spectroscopic Analysis of the Galactic Globular Cluster NGC 6273 (M19)

et al. 2015

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A combined effort utilizing spectroscopy and photometry has revealed the existence of a new globular cluster class. These "anomalous" clusters, which we refer to as "iron-complex" clusters, are differentiated from normal clusters by exhibiting large (0.10 dex) intrinsic metallicity dispersions, complex sub-giant branches, and correlated [Fe/H] and s-process enhancements. In order to further investigate this phenomenon, we have measured radial velocities and chemical abundances for red giant branch stars in the massive, but scarcely studied, globular cluster NGC 6273. The velocities and abundances were determined using high resolution (R ∼ 27,000) spectra obtained with the Michigan/ Magellan Fiber System (M2FS) and MSpec spectrograph on the Magellan-Clay 6.5 m telescope at Las Campanas Observatory. We find that NGC 6273 has an average heliocentric radial velocity of +144.49 km s −1 (σ = 9.64 km s

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“…similar metallicity and is believed to be the long-lived remnant of the first generation (FG) formed in the cluster. The other, with a modified composition, is the second generation (SG), polluted by the most massive stars of the FG with ejecta from H burning at high temperature (Denisenkov & Denisenkova 1989;Langer et al 1993). Unfortunately, the question of which FG stars produced the gas of modified composition is still unsettled (see e.g.…”

Section: Introductionmentioning

confidence: 99%

NGC 6535: the lowest mass Milky Way globular cluster with a Na-O anti-correlation?

Bragaglia

Carretta

D’Orazi

et al. 2017

A&A

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To understand globular clusters (GCs) we need to comprehend how their formation process was able to produce their abundance distribution of light elements. In particular, we seek to figure out which stars imprinted the peculiar chemical signature of GCs. One of the best ways is to study the light-element anti-correlations in a large sample of GCs that are analysed homogeneously. As part of our spectroscopic survey of GCs with FLAMES, we present here the results of our study of about 30 red giant member stars in the low-mass, low-metallicity Milky Way cluster NGC 6535. We measured the metallicity (finding [Fe/H]=−1.95, rms=0.04 dex in our homogeneous scale) and other elements of the cluster and, in particular, we concentrate here on O and Na abundances. These elements define the normal Na-O anti-correlation of classical GCs, making NGC 6535 perhaps the lowest mass cluster with a confirmed presence of multiple populations. We updated the census of Galactic and extragalactic GCs for which a statement on the presence or absence of multiple populations can be made on the basis of high-resolution spectroscopy preferentially, or photometry and low-resolution spectroscopy otherwise; we also discuss the importance of mass and age of the clusters as factors for multiple populations.

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The Problem of Orphanhood in Contemporary Russia: The Psychological Aspect

Cited by 39 publications

References 0 publications

The normal chemistry of multiple stellar populations in the dense globular cluster NGC 6093 (M 80)

The normal chemistry of multiple stellar populations in the dense globular cluster NGC 6093 (M 80)

A Spectroscopic Analysis of the Galactic Globular Cluster NGC 6273 (M19)

NGC 6535: the lowest mass Milky Way globular cluster with a Na-O anti-correlation?

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