NGC6362: the least massive globular cluster with chemically distinct multiple populations

Abstract

We present the first measure of Fe and Na abundances in NGC 6362, a low-mass globular cluster where first and second generation stars are fully spatially mixed. A total of 160 member stars (along the red giant branch and the red horizontal branch) have been observed with the multi-object spectrograph FLAMES at the Very Large Telescope. We find that the cluster has an iron abundance of [Fe/H]=--1.09$\pm$0.01 dex, without evidence of intrinsic dispersion. On the other hand, the [Na/Fe] distribution turns out to be intrinsically broad and bimodal. The Na-poor and Na-rich stars populate, respectively, the bluest and the reddest red giant branches detected in the color-magnitude diagrams including the U filter. The red giant branch is composed of a mixture of first and second generation stars in a similar proportion, while almost all the red horizontal branch stars belong to the first cluster generation. Until now, NGC 6362 is the least massive globular cluster where both the photometric and spectroscopic signatures of multiple populations have been detected.

Accepted for publication by ApJ; 22 pages, 7 figures, 1 table

References in corpus (49)

• Multiple populations in globular clusters. Lessons learned from the Milky Way globular clusters
• Resolved Massive Star Clusters in the Milky Way and its Satellites: Brightness Profiles and a Catalogue of Fundamental Parameters
• Fast rotating massive stars and the origin of the abundance patterns in galactic globular clusters
• A Triple Main Sequence in the Globular Cluster NGC 2808
• Intrinsic iron spread and a new metallicity scale for Globular Clusters
• Formation and Dynamical Evolution of Multiple Stellar Generations in Globular Clusters
• A large stellar evolution database for population synthesis studies. II. Stellar models and isochrones for an alpha-enhanced metal distribution
• Omega Centauri: The Population Puzzle Goes Deeper
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. I. Overview of the Project and Detection of Multiple Stellar Populations
• Massive binaries as the source of abundance anomalies in globular clusters
• Non-LTE calculations for neutral Na in late-type stars using improved atomic data
• Spectroscopic and Photometric evidence of two stellar populations in the Galactic Globular Cluster NGC6121 (M4)
• Modeling the Metallicity Distribution of Globular Clusters
• Globular clusters as the relics of regular star formation in 'normal' high-redshift galaxies
• The ACS Survey of Galactic Globular Clusters. III. The Double Subgiant Branch of NGC 1851
• Super-Massive Stars as a Source of Abundance Anomalies of Proton-Capture Elements in Globular Clusters
• Early Disc Accretion as the Origin of Abundance Anomalies in Globular Clusters
• DAOSPEC: an automatic code for measuring equivalent widths in high-resolution stellar spectra
• Photometric signatures of multiple stellar populations in Galactic globular clusters
• Dynamical Evolution and Spatial Mixing of Multiple Population Globular Clusters
• News from the Galactic suburbia: the chemical composition of the remote globular cluster NGC 2419
• Hubble Space Telescope reveals multiple Sub-Giant Branch in eight Globular Clusters
• Looking outside the Galaxy: the discovery of chemical anomalies in 3 old Large Magellanic Cloud clusters
• Secondary star formation within massive star clusters: Origin of multiple stellar populations in globular clusters
• Mining SDSS in search of Multiple Populations in Globular Clusters
• Sodium-Oxygen anticorrelation among Horizontal Branch Stars in the Globular Cluster M4
• Rotations and Abundances of Blue Horizontal-Branch Stars in Globular Cluster M15
• Multiple stellar populations in the Galactic globular cluster NGC 6752
• The peculiar Horizontal Branch of NGC 2808
• Globular Cluster Mass Loss in the Context of Multiple Populations
• Lithium abundance in the globular cluster M4: from the Turn-Off to the RGB Bump
• GALA: an automatic tool for the abundance analysis of stellar spectra
• The Na-O anticorrelation in horizontal branch stars. III. 47 Tuc and M 5
• Searching for multiple stellar populations in the massive, old open cluster Berkeley 39
• Low-resolution spectroscopy of main sequence stars belonging to 12 Galactic globular clusters. I. CH and CN band strength variations
• Sodium and Oxygen Abundances in the Open Cluster NGC 6791 from APOGEE H-Band Spectroscopy
• First evidence of fully spatially mixed first and second generations in globular clusters: the case of NGC 6362
• The Na-O anticorrelation in horizontal branch stars. I. NGC 2808
• The Unique Na:O Abundance Distribution in NGC 6791: The First Open(?) Cluster with Multiple Populations
• Searching for Chemical Signatures of Multiple Stellar Populations in the Old, Massive Open Cluster NGC 6791
• The primordial and evolutionary abundance variations in globular-cluster stars: a problem with two unknowns
• Formation of Multiple Populations in Globular Clusters: constraints on the dilution by pristine gas
• The Na-O anticorrelation in horizontal branch stars. II. NGC1851
• Evidence of tidal distortions and mass loss from the old open cluster NGC 6791
• High resolution reddening map in the direction of the stellar system Terzan 5
• CN Variations in High Metallicity Globular and Open Clusters
• The Dynamics of Multiple Populations in the Globular Cluster NGC 6362
• Evidence for multiple populations in the massive globular cluster NGC 2419 from deep uVI LBT photometry
• NGC 5694: another foster son of the Galactic Halo

Cited by in corpus (30)

• What is a globular cluster? An observational perspective
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XIX. A Chemical Tagging of the Multiple Stellar Populations Over the Chromosome Maps
• Multiple populations in the old and massive Small Magellanic Cloud globular cluster NGC121
• NGC 6535: the lowest mass Milky Way globular cluster with a Na-O anti-correlation? Cluster mass and age in the multiple population context
• The Search for Multiple Populations in Magellanic Cloud Clusters I: Two Stellar Populations in the Small Magellanic Cloud Globular Cluster NGC 121
• Evidence for multiple populations in the intermediate age cluster Lindsay 1 in the SMC
• The Relationship Between Globular Cluster Mass, Metallicity, and Light Element Abundance Variations
• Ages of the Bulge globular clusters NGC 6522 and NGC 6626 (M28) from HST Proper-motion-cleaned Color-Magnitude Diagrams
• The chemical composition of the low-mass Galactic globular cluster NGC 6362
• The unexpected kinematics of multiple populations in NGC6362: do binaries play a role?
• Gas expulsion vs gas retention in young stellar clusters II: effects of cooling and mass segregation
• Detailed chemical composition and orbit of the new globular cluster FSR1758: Implications for the accretion of the Sequoia dwarf galaxy onto the Milky Way
• 3D core kinematics of NGC 6362: central rotation in a dynamically evolved globular cluster
• NGC 6791: a probable bulge cluster without multiple populations
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XX. Ages of single and multiple stellar populations in seven bulge globular clusters
• Multiple populations in massive star clusters under the magnifying glass of photometry: Theory and tools
• ESO452-SC11: The lowest mass globular cluster with a potential chemical inhomogeneity
• Confirmation of a metallicity spread amongst first population stars in globular clusters
• A Model for Clumpy Self-Enrichment in Globular Clusters
• 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
• Reversed radial distribution trend of subpopulations in the globular clusters NGC 362 and NGC 6723
• A 3D view of multiple populations kinematics in Galactic globular clusters
• Photometric characterization of multiple populations in star clusters: The impact of the first dredge-up
• Chemical abundance analysis of red giant branch stars in the globular cluster E3
• A Nitrogen-Enhanced Metal-Poor star discovered in the globular cluster ESO280-SC06
• Isochrone fitting of Galactic globular clusters -- IV. NGC6362 and NGC6723
• Chemical analysis of eight giant stars of the globular cluster NGC 6366
• Stellar collisions in globular clusters: Constraints on the initial mass function of the first generation of stars
• Metallicity and distance of NGC 6362 from its RR Lyrae and SX Phoenicis stars
• Globular Cluster Intrinsic Iron Abundance Spreads: I. Catalog