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We present an analysis of the multiple stellar populations of the globular cluster NGC 1851. We used lower resolution spectra of giant stars to measure CN, CH, and calcium H & K spectral indices, and determine elemental abundances for…

Solar and Stellar Astrophysics · Physics 2016-10-31 Jeffrey D. Simpson , Sarah L. Martell , Colin A. Navin

About one-fifth of the Galactic globular clusters (GCs), dubbed Type II GCs, host distinct stellar populations with different heavy elements abundances. NGC 1851 is one of the most studied Type II GCs, surrounded by several controversies…

We present the abundance analysis of a sample of more than 120 red giants in the globular cluster (GC) NGC 1851, based on FLAMES spectra. We find a small but detectable metallicity spread. This spread is compatible with the presence of two…

In the last years, photometric and spectroscopic evidence has demonstrated that many, maybe all the Globular Clusters (GC) host multiple stellar populations. High-resolution spectroscopy has established that, while most GCs are…

Solar and Stellar Astrophysics · Physics 2011-07-13 A. P. Milone , G. Piotto , R. L. Bedin , A. F. Marino , Y. Momany , S. Villanova

Context. NGC 1851 is one of several globular clusters for which multiple stellar populations of the subgiant branch have been clearly identified and a difference in metallicity detected. A crucial piece of information on the formation…

We present the abundances of N in a sample of 62 stars on the red giant branch (RGB) in the peculiar globular cluster NGC 1851. The values of [N/Fe] ratio were obtained by comparing the flux measured in the observed spectra with that from…

Astrophysics of Galaxies · Physics 2014-03-05 Eugenio Carretta , Valentina D'Orazi , Raffaele G. Gratton , Sara Lucatello

We present the chemical compositions for eight bright giants in the globular cluster NGC 1851. Our analysis reveals large star-to-star abundance variations and correlations of the light elements O, Na, and Al, a feature found in every well…

Astrophysics · Physics 2009-11-13 David Yong , Frank Grundahl

There is a growing body of evidence for the presence of multiple stellar populations in some globular clusters, including NGC 1851. For most of these peculiar globular clusters, however, the evidence for the multiple red giant-branches…

Astrophysics of Galaxies · Physics 2014-11-20 Sang-Il Han , Young-Wook Lee , Seok-Joo Joo , Sangmo Tony Sohn , Suk-Jin Yoon , Hak-Sub Kim , Jae-Woo Lee

NGC1851 possibly shows a spread in [Fe/H], but the relation between this spread and the division in the SGB is unknown. We obtained blue (3950-4600 A) intermediate resolution (R~8,000) spectra for 47 stars on the bright and 30 on the faint…

Solar and Stellar Astrophysics · Physics 2015-06-05 R. G. Gratton , S. Villanova , S. Lucatello , A. Sollima , D. Geisler , E. Carretta , S. Cassisi , A. Bragaglia

There is increasing evidence that some massive globular clusters (GCs) host multiple stellar populations having different heavy element abundances enriched by supernovae. They usually accompany multiple red giant branches (RGBs) in the…

Astrophysics of Galaxies · Physics 2015-06-12 Seok-Joo Joo , Young-Wook Lee

We study the distribution of aluminum abundances among red giants in the peculiar globular cluster NGC 1851. Aluminum abundances were derived from the strong doublet Al I 8772-8773 A measured on intermediate resolution FLAMES spectra of 50…

Astrophysics of Galaxies · Physics 2015-06-05 Eugenio Carretta , Valentina D'Orazi , Raffaele G. Gratton , Sara Lucatello

The chemical composition of multiple populations in the massive globular cluster (GC) NGC~2808 is addressed with the homogeneous abundance re-analysis of 140 red giant branch (RGB) stars. UVES spectra for 31 stars and GIRAFFE spectra for…

Solar and Stellar Astrophysics · Physics 2015-09-23 Eugenio Carretta

NGC 5053 provides a rich environment to test our understanding of the complex evolution of globular clusters (GCs). Recent studies have found that this cluster has interesting morphological features beyond the typical spherical distribution…

Astrophysics of Galaxies · Physics 2015-05-20 Owen M. Boberg , Eileen D. Friel , Enrico Vesperini

We present chemical abundance analysis of a sample of 15 red giant branch (RGB) stars of the Globular Cluster NGC~1851 distributed along the two RGBs of the (v, v-y) CMD. We determined abundances for C+N+O, Na, $\alpha$, iron-peak, and…

Astrophysics of Galaxies · Physics 2015-05-19 Sandro Villanova , Douglas Geisler , Giampaolo Piotto

The FLAMES survey ``Na-O anti-correlation and HB" uncovered the modern standard for globular clusters (GCs), that is their ubiquitous multiple stellar populations (MPs) distinct by the abundance of proton-capture elements. That survey can…

Solar and Stellar Astrophysics · Physics 2026-03-25 Eugenio Carretta

We present a new method to estimate the fraction of stars with chemical composition of first and second(s) generation(s) currently hosted in Galactic globular clusters (GCs). We compare cluster and field stars of similar metallicity in the…

Astrophysics of Galaxies · Physics 2015-06-16 Eugenio Carretta

We present the first comprehensive abundance study of the massive, outer halo globular cluster (GC) M 75 (NGC 6864). This unique system shows a very extended trimodal horizontal branch (HB), but no other clues for multiple populations have…

Astrophysics of Galaxies · Physics 2013-01-11 Nikolay Kacharov , Andreas Koch

We present aluminium, magnesium, and silicon abundances in the metal-poor globular cluster NGC 6752 for a sample of more than 130 red giants with homogeneous oxygen and sodium abundances. We find that [Al/Fe] shows a spread of about 1.4 dex…

Astrophysics of Galaxies · Physics 2015-06-04 Eugenio Carretta , Angela Bragaglia , Raffaele Gratton , Sara Lucatello , Valentina D'Orazi

Recent observations have shown that a growing number of the most massive Galactic globular clusters contain multiple populations of stars with different [Fe/H] and neutron-capture element abundances. NGC 6273 has only recently been…

Our understanding of multiple populations in globular clusters (GCs) largely comes from photometry and spectroscopy: appropriate photometric diagrams can disentangle first and second populations (1P and 2P)-1P having chemical signatures…

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