The chemical composition of the low-mass Galactic globular cluster NGC 6362★

Massari, D.; Mucciarelli, A.; Dalessandro, E.; Bellazzini, M.; Cassisi, S.; Fiorentino, G.; Ibata, Rodrigo; Lardo, C.; Salaris, Maurizio

doi:10.1093/mnras/stx549

Cited by 39 publications

(34 citation statements)

References 77 publications

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“…A deep photometric analysis performed by Piotto et al (2015) and Milone et al (2017) using UV-optical HST data, clearly revealed the presence of these two stellar populations even for the MS stars. These results were recently corroborated by the high-resolution spectroscopic analysis performed by Mucciarelli et al (2016) and Massari et al (2017).…”

Section: Testing the Presence Of Multiple Stellar Populationssupporting

confidence: 54%

“…In contrast with the results for NGC 6522 and NGC 6626, Table 5 shows that the goodness of fit for NGC 6362 does not favor helium enhancement using BaSTI models, and for DSED models, a canonical helium is clearly favored. Assuming a helium abundance of Y ∼ 0.25, and a metallicity taken as the average between the two most recent determinations ([Fe/H]= −1.08; Mucciarelli et al 2016;Massari et al 2017), we get an intrinsic distance modulus of 14.39 (BaSTI) or 14.46 (DSED) and E(B −V ) of 0.050 (BaSTI) or 0.055 (DSED). Figure 14 summarizes the best isochrone fits to the MSTO, SGB, and RGB from the statistical analysis, together with the newly calculated tracks for the ZAHB, with all models from BaSTI.…”

Section: Ngc 6362mentioning

confidence: 99%

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Ages of the Bulge Globular Clusters NGC 6522 and NGC 6626 (M28) from HST Proper-motion-cleaned Color–Magnitude Diagrams*

Kerber

Nardiello

Ortolani

et al. 2018

ApJ

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Bulge globular clusters (GCs) with metallicities [Fe/H]−1.0 and blue horizontal branches are candidates to harbor the oldest populations in the Galaxy. Based on the analysis of HST proper-motion-cleaned color-magnitude diagrams in filters F435W and F625W, we determine physical parameters for the old bulge GCs NGC 6522 and NGC 6626 (M28), both with well-defined blue horizontal branches. We compare these results with similar data for the inner halo cluster NGC 6362. These clusters have similar metallicities (−1.3[Fe/H]−1.0) obtained from high-resolution spectroscopy. We derive ages, distance moduli, and reddening values by means of statistical comparisons between observed and synthetic fiducial lines employing likelihood statistics and the Markov chain Monte Carlo method. The synthetic fiducial lines were generated using α-enhanced BaSTI and Dartmouth stellar evolutionary models, adopting both canonical (Y∼0.25) and enhanced (Y∼0.30-0.33) helium abundances. RR Lyrae stars were employed to determine the HB magnitude level, providing an independent indicator to constrain the apparent distance modulus and the helium enhancement. The shape of the observed fiducial line could be compatible with some helium enhancement for NGC 6522 and NGC 6626, but the average magnitudes of RR Lyrae stars tend to rule out this hypothesis. Assuming canonical helium abundances, BaSTI and Dartmouth models indicate that all three clusters are coeval, with ages between ∼12.5 and 13.0 Gyr. The present study also reveals that NGC 6522 has at least two stellar populations, since its CMD shows a significantly wide subgiant branch compatible with 14%±2% and 86%±5% for first and second generations, respectively.

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Section: Testing the Presence Of Multiple Stellar Populationssupporting

confidence: 54%

Section: Ngc 6362mentioning

confidence: 99%

Ages of the Bulge Globular Clusters NGC 6522 and NGC 6626 (M28) from HST Proper-motion-cleaned Color–Magnitude Diagrams*

Kerber

Nardiello

Ortolani

et al. 2018

ApJ

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“…Two evolutionary tracks (for the indicated masses, in solar units) have also been plotted in each panel to illustrate their strong morphological dependence on Y Mucciarelli et al (2016),. andMassari et al (2017). As first reported byDalessandro et al (2014),Mucciarelli et al.…”

mentioning

confidence: 56%

Constraints on the Distance Moduli, Helium and Metal Abundances, and Ages of Globular Clusters from their RR Lyrae and Non-variable Horizontal-branch Stars. III. M55 and NGC 6362

VandenBerg

Denissenkov

2018

ApJ

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M 55 (NGC 6809) and NGC 6362 are among the few globular clusters for which masses and radii have been derived to high precision for member binary stars. They also contain RR Lyrae variables which, together with their non-variable horizontal-branch (HB) populations, provide tight constraints on the cluster reddenings and distance moduli through fits of stellar models to their pulsational and evolutionary properties. Reliable (m − M ) V estimates yield M V and M bol values of comparable accuracy for binary stars because the V -band bolometric corrections applicable to them have no more than a weak dependence on effective temperature (T eff ) and [Fe/H]. Chemical abundances derived from the binary mass-M V relations are independent of determinations based on their spectra. The temperatures of the binaries, which are calculated directly from their luminosities and the measured radii, completely rule out the low T eff scale that has been determined for metal-deficient stars in some recent spectroscopic and interferometric studies. If [α/Fe] = 0.4 and [O/Fe] = 0.5 ± 0.1, we find that M 55 has (m − M ) V = 13.95 ± 0.05, [Fe/H] = −1.85 ± 0.1, and an age of 12.9 ± 0.8 Gyr, whereas NGC 6362 has (m − M ) V = 14.56 ± 0.05, [Fe/H] = −0.90 ± 0.1, and an age of 12.4 ± 0.8 Gyr. The HB of NGC 6362 shows clear evidence for multiple stellar populations. Constraints from the RR Lyrae standard candle and from local subdwarfs (with Gaia DR2 parallaxes) are briefly discussed.

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“…For Ni, NGC 6723 (Gratton et al 2015), Mercer 5 (Peñaloza et al 2015), NGC 6342 (Johnson et al 2016) and NGC 6553 (Cohen et al 1999). metalrich GCs with R GC > 4.5 kpc: NGC 6362 (Massari et al 2017), M 71 (Ramírez & Cohen 2002) and 47 Tuc . Field: bulge from Johnson et al (2014) for Ni, and from Barbuy et al (2013) for Mn.…”

Section: Light Odd-z Elementsmentioning

confidence: 99%

Chemical analysis of eight giant stars of the globular cluster NGC 6366

Puls

Alves-Brito

Campos

et al. 2018

Monthly Notices of the Royal Astronomical Society

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The metal-rich Galactic globular cluster NGC 6366 is the fifth closest to the Sun. Despite its interest, it has received scarce attention, and little is known about its internal structure. Its kinematics suggests a link to the halo, but its metallicity indicates otherwise. We present a detailed chemical analysis of eight giant stars of NGC 6366, using high resolution and high quality spectra (R > 40 000, S/N > 60) obtained at the VLT (8.2 m) and CFHT (3.6 m) telescopes. We attempted to characterize its chemistry and to search for evidence of multiple stellar populations. The atmospheric parameters were derived using the method of excitation and ionization equilibrium of Fe i and Fe ii lines and from those atmospheric parameters we calculated the abundances for other elements and found that none of the elements measured presents star-tostar variation greater than the uncertainties. We compared the derived abundances with those of other globular clusters and field stars available in the literature. We determined a mean [Fe/H] = −0.60 ± 0.03 for NGC 6366 and found some similarity of this object with M 71, another inner halo globular cluster. The Na-O anticorrelation extension is short and no star-to-star variation in Al is found. The presence of second generation stars is not evident in NGC 6366.

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The chemical composition of the low-mass Galactic globular cluster NGC 6362★

Cited by 39 publications

References 77 publications

Ages of the Bulge Globular Clusters NGC 6522 and NGC 6626 (M28) from HST Proper-motion-cleaned Color–Magnitude Diagrams*

Ages of the Bulge Globular Clusters NGC 6522 and NGC 6626 (M28) from HST Proper-motion-cleaned Color–Magnitude Diagrams*

Constraints on the Distance Moduli, Helium and Metal Abundances, and Ages of Globular Clusters from their RR Lyrae and Non-variable Horizontal-branch Stars. III. M55 and NGC 6362

Chemical analysis of eight giant stars of the globular cluster NGC 6366

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