The two metallicity groups of the globular cluster M 22: a chemical perspective

By A. Marino, C. Sneden, R. P. Kraft, G. Wallersteín, J. Norris, G. Costa, A. Milone, I. Ivans, G. Gonzalez, Jon P. Fulbright and 5 more. 2011

163 citations recorded by the source corpus.

We present a detailed chemical composition analysis of 35 red giant stars in the globular cluster M22. High resolution spectra for this study were obtained at five observatories, and analyzed in a uniform manner. We have determined abundances of representative light proton-capture, , Fe-peak and neutron-capture element groups. Our aim is to better understand the peculiar chemical enrichment history of this cluster, in which two stellar groups are characterized by a di erent content in iron, neutron capture elements Y, Zr and Ba, and element Ca. The principal results of this study are: (i) substantial star-to-star metallicity scatter ( 2.0 . [Fe/H] . 1.6); (ii) enhancement of s-process/r-process neutron-capture abundance ratios in a fraction of giants, positively correlated with metallicity; (iii) sharp separation between the s-process-rich and s-process-poor groups by [La/Eu] ratio; (iv) possible increase of [Cu/Fe] ratios with increasing [Fe/H], suggesting that this element also has a significant s-process component; and (v) presence of Na-O and C-N anticorrelations in both the stellar groups.

Subfields: Astronomy and Astrophysics, Electronic, Optical and Magnetic Materials, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/bfa4d0a320ddaebb0a8cd480483c45783974c9d0

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Nuclear and High Energy Physics

Citations in the corpus

The Hubble Space Telescope UV Legacy Survey of Galactic globular clusters – IX. The Atlas of multiple stellar populations (2016, background): “This indicates that faint-SGBstars are either enhanced in their C+N+O overall abundance, or are older than stars on the bright SGB by∼ 1−2Gyr (Cassisi et al. 2008; Ventura et al. 2009; Marino et al. 2011).”
The Hubble Space TelescopeUV Legacy Survey of Galactic Globular Clusters – V. Constraints on formation scenarios (2015, background): “Exceptions are the well known cases ofω Cen and Terzan 5, but less extreme metallicity differences are now documented for quite a few other clusters such as M2, M22, M54, NGC 185, NGC 5286 and NGC 5824 (see Paper I and Marino et al. 2011, for references).”
The ACS survey of Galactic globular clusters. XII. Photometric binaries along the main sequence (2011, background): “In this case theoretical isochrones show that the measured [Fe/H] difference of∼0.15 dex do not produce any appreciablemF606W−mF814W color bimodality among MS stars (Marino et al. 2009, 2011).”
THE HUBBLE SPACE TELESCOPE UV LEGACY SURVEY OF GALACTIC GLOBULAR CLUSTERS. I. OVERVIEW OF THE PROJECT AND DETECTION OF MULTIPLE STELLAR POPULATIONS (2014, background): “The GO-12311 – 11 – data set is now complemented by F336W and F438W WFC3/UVIS images for NGC 1851, M4, and M22.”
Target Selection for the SDSS-IV APOGEE-2 Survey (2017, background): “O), as well as the full observed range of [Fe/H] in the clusters where a spread in [Fe/H] has been observed (e.g., Marino et al. 2011; Villanova et al. 2014).”